7 ms·

Ask HN/PG: What causes this sudden drop-off behaviour on HN submissions?

93 points by dazbradbury 14y ago

dazbradbury 14y ago
It seems unlikely that this is algorithmic, hence, I would guess if a post is deemed to not be meeting HN standards / guidelines, moderators can "demote" a post, essentially removing it from the front page. So in this case, was the title simply too link-baity? And who judges that? This is obviously a guess, and looking through the FAQ (Official and unofficial!), I can't seem to see it stated anywhere. Another possibility could be user flagging, but that would seem too easy to game maliciously. I think whilst some elements of your filtering you want to keep secret to stop spammers, it would be helpful to understand this throttling behaviour to help people submit better content. Transparency is often helpful to create less work for both sides, so if an answer could be given, I think people would be interested to know!
- andrewcooke 14y ago
  i don't know how current it is, but i believe that hn source is included in the arc download - see http://news.ycombinator.com/item?id=1390685 http://news.ycombinator.com/item?id=1390685 - so you could try looking there to see how flagging is handled.
  - rpm4321 14y ago
    My impression is that quite a bit of the source for flagging, vote-ring, and spam detection isn't included in the arc download, for obvious reasons.
  - dazbradbury 14y ago
    Good point - could be in here, but it's 1:30am and I probably shouldn't be learning Arc right now! Will take a look in the morning. (= flag-threshold* 30 flag-kill-threshold* 7 many-flags* 1) ; Un-flagging something doesn't unkill it, if it's now no longer ; over flag-kill-threshold. Ok, since arbitrary threshold anyway. (def flaglink (i user whence) (when (and user (isnt user i!by) (or (admin user) (> (karma user) flag-threshold*))) (pr bar*) (w/rlink (do (togglemem user i!flags) (when (and (~mem 'nokill i!keys) (len> i!flags flag-kill-threshold*) (~find admin:!2 i!vote)) (kill i 'flags)) whence) (pr "@(if (mem user i!flags) 'un)flag")) (when (and (admin user) (len> i!flags many-flags*)) (pr bar* (plural (len i!flags) "flag") " ") (w/rlink (do (togglemem 'nokill i!keys) (save-item i) whence) (pr (if (mem 'nokill i!keys) "un-notice" "noted"))))))
    - wavesounds 14y ago
      This is the craziest programming language I have ever seen.
weaksauce 14y ago
Probably the algorithm, check out these(old) posts on it... http://amix.dk/blog/post/19574 http://amix.dk/blog/post/19574 http://news.ycombinator.com/item?id=1781013 http://news.ycombinator.com/item?id=1781013
- dazbradbury 14y ago
  Those posts describe a smooth drop off as a function of time and votes - in some instances (such as the one linked to) that clearly isn't the case.
  - legierski 14y ago
    I'm wondering if there's any description of the voting ring detector used by HN
_sentient 14y ago
Are there any YC companies competing directly in the space? 42Floors comes to mind, although I believe they are focused exclusively on commercial real estate at the moment. If there is a YC company that competes directly with you, I could see incentive for a mod to suppress your post. </tinfoil hat speculation>
- dazbradbury 14y ago
  There have been several YC-backed rental/property startups, but it seems a little far-fetched that pg/yc would get admins to suppress competitor stories. I'm sure there are plenty of examples of competitor start-ups reaching, and staying on, the front page that could rule that theory out.
- ximeng 14y ago
  It's not tinfoil hat speculation. Sharp dropoffs also happened when the story of an AirBNB house being robbed broke. Rather than just seeing one story dropping off we need a way to see every time this happens to make our own minds up over whether it's above board.
  - deleted 14y ago
    [deleted]
  - rpm4321 14y ago
    From everything I know about PG and YC, I highly doubt they themselves would take that kind of action unless a post was outright slander. It just seems Nixonian. That said, there is obviously quite a bit of goodwill on HN for PG and YC. You could call it fanboyism if you were feeling uncharitable. To me, that seems a much more likely scenario - an anti-YC submission getting a bunch of flag votes, rather than an intervention by admins.
    - ximeng 14y ago
      Agree, plenty of goodwill from me as well, which is why I was surprised to see a popular voted question about a YC company having trouble suddenly disappear then. Without a good explanation it makes me lose trust in the transparency of HN, whether due to flag votes or direct intervention.
mrmaddog 14y ago
It looks like this "Show HN" post wouldn't have a high "gag" score [1], so either the post has been flagged multiple times (unlikely), or, most likely, the majority of those early votes came from the same location, causing the voting ring safeguards [2] to kick in. [1] http://news.ycombinator.com/item?id=1782058 http://news.ycombinator.com/item?id=1782058 [2] http://news.ycombinator.com/item?id=3894695 http://news.ycombinator.com/item?id=3894695
- dazbradbury 14y ago
  Unfortunately, I know this wasn't the case - I didn't provide the link to anyone in our office, which has it's own IP, and I know they weren't aware of the HN post until afterwards. I also wouldn't publicly use this as an example if I knew I had been rigging the votes! So maybe it was just a case of HNers flagging the story as it became popular, as the title was fairly link-baity? I was under the impression that flagging a story kills it rather than suppresses it, but regardless, if that's the case then it makes sense. Edit: One comment in your example link by ColinWright seems to state 2 or more "flags" can cause this behaviour: http://news.ycombinator.com/item?id=3893207 http://news.ycombinator.com/item?id=3893207 If that's the case, it's probably best people don't know about it, as used maliciously it would be fairly disruptive.
  - jtheory 14y ago
    > Unfortunately, I know this wasn't the case You can't know -- just because it wasn't in your office doesn't mean it didn't happen. One of the first readers to see it may have mass emailed his/her colleagues who all read/upvoted when they got into work in the morning, for example....
pg 14y ago
You set off the voting ring detector.
- dazbradbury 14y ago
  Thanks for responding, and I don't mean to waste your time, but that seems like a bug. We have a single ip, that 4 people can use, and none of them knew of the hn post until after the post was demoted. In fact, I don't think any of them have a hn account! On top of this, I didn't share the link with anyone, and the votes appeared to be totally organic. Our target market is not the hn crowd, and this subsequent post was merely out of curiosity, so I have very little to gain by lying. Edit: if you or your team wanted any more information for debugging purposes I would be happy to oblige, just let me know if I can help, though I understand if this is fairly low priority!
  - jQueryIsAwesome 14y ago
    It maybe set off the vote ring detector because your costumers seem to be located all around London. So it may be possible that some of them shared the submission with other London users or that because they know your company they up-vote it; making it look like it was ringed but it was just selection bias. Anyway this is a tricky problem; because at the end of the day intent is a fundamental part of vote rings and that can be really hard to see by algorithms alone.
- flipside 14y ago
  Can you share anything about how you define a voting ring?
  - zitterbewegung 14y ago
    Probably doing so might tip off the people who try to game HN so I don't think its a good idea to share that kind of information.
    - deleted 14y ago
      [deleted]
TallboyOne 14y ago
What I want to know is how I get tons of HN traffic daily months after my post is off the front page.
- evilduck 14y ago
  Search engine results. The comments are indexed and are often niche enough to dominate certain search terms.
- MaysonL 14y ago
  Probably it's search generated...
supersaiyan 14y ago
Can I ask what js framework/proj. you are using to graph the data?
- jpalacios 14y ago
  looks like highcharts JS
JeremyMorgan 14y ago
Because you're on the 15th page by then?
zerostar07 14y ago
You 're all entrepreneurs (or wannapreneurs). Why doesn't one of you create a service that will employ mechanical turks as seed to bootstrap a new website by using it and providing honest feedback? I know i would pay for that. Being on the frontpage in HN will not guarantee seed userbase; it's more of an ego boost.

93 points by dazbradbury 14y ago

It seems unlikely that this is algorithmic, hence, I would guess if a post is deemed to not be meeting HN standards / guidelines, moderators can "demote" a post, essentially removing it from the front page. So in this case, was the title simply too link-baity? And who judges that? This is obviously a guess, and looking through the FAQ (Official and unofficial!), I can't seem to see it stated anywhere. Another possibility could be user flagging, but that would seem too easy to game maliciously. I think whilst some elements of your filtering you want to keep secret to stop spammers, it would be helpful to understand this throttling behaviour to help people submit better content. Transparency is often helpful to create less work for both sides, so if an answer could be given, I think people would be interested to know!

andrewcooke 14y ago
i don't know how current it is, but i believe that hn source is included in the arc download - see http://news.ycombinator.com/item?id=1390685 http://news.ycombinator.com/item?id=1390685 - so you could try looking there to see how flagging is handled.
- rpm4321 14y ago
  My impression is that quite a bit of the source for flagging, vote-ring, and spam detection isn't included in the arc download, for obvious reasons.
- dazbradbury 14y ago
  Good point - could be in here, but it's 1:30am and I probably shouldn't be learning Arc right now! Will take a look in the morning. (= flag-threshold* 30 flag-kill-threshold* 7 many-flags* 1) ; Un-flagging something doesn't unkill it, if it's now no longer ; over flag-kill-threshold. Ok, since arbitrary threshold anyway. (def flaglink (i user whence) (when (and user (isnt user i!by) (or (admin user) (> (karma user) flag-threshold*))) (pr bar*) (w/rlink (do (togglemem user i!flags) (when (and (~mem 'nokill i!keys) (len> i!flags flag-kill-threshold*) (~find admin:!2 i!vote)) (kill i 'flags)) whence) (pr "@(if (mem user i!flags) 'un)flag")) (when (and (admin user) (len> i!flags many-flags*)) (pr bar* (plural (len i!flags) "flag") " ") (w/rlink (do (togglemem 'nokill i!keys) (save-item i) whence) (pr (if (mem 'nokill i!keys) "un-notice" "noted"))))))
  - wavesounds 14y ago
    This is the craziest programming language I have ever seen.

weaksauce 14y ago

Probably the algorithm, check out these(old) posts on it... http://amix.dk/blog/post/19574 http://amix.dk/blog/post/19574 http://news.ycombinator.com/item?id=1781013 http://news.ycombinator.com/item?id=1781013

dazbradbury 14y ago
Those posts describe a smooth drop off as a function of time and votes - in some instances (such as the one linked to) that clearly isn't the case.
- legierski 14y ago
  I'm wondering if there's any description of the voting ring detector used by HN

_sentient 14y ago

Are there any YC companies competing directly in the space? 42Floors comes to mind, although I believe they are focused exclusively on commercial real estate at the moment. If there is a YC company that competes directly with you, I could see incentive for a mod to suppress your post. </tinfoil hat speculation>

dazbradbury 14y ago
There have been several YC-backed rental/property startups, but it seems a little far-fetched that pg/yc would get admins to suppress competitor stories. I'm sure there are plenty of examples of competitor start-ups reaching, and staying on, the front page that could rule that theory out.
ximeng 14y ago
It's not tinfoil hat speculation. Sharp dropoffs also happened when the story of an AirBNB house being robbed broke. Rather than just seeing one story dropping off we need a way to see every time this happens to make our own minds up over whether it's above board.
- deleted 14y ago
  [deleted]
- rpm4321 14y ago
  From everything I know about PG and YC, I highly doubt they themselves would take that kind of action unless a post was outright slander. It just seems Nixonian. That said, there is obviously quite a bit of goodwill on HN for PG and YC. You could call it fanboyism if you were feeling uncharitable. To me, that seems a much more likely scenario - an anti-YC submission getting a bunch of flag votes, rather than an intervention by admins.
  - ximeng 14y ago
    Agree, plenty of goodwill from me as well, which is why I was surprised to see a popular voted question about a YC company having trouble suddenly disappear then. Without a good explanation it makes me lose trust in the transparency of HN, whether due to flag votes or direct intervention.

mrmaddog 14y ago

It looks like this "Show HN" post wouldn't have a high "gag" score [1], so either the post has been flagged multiple times (unlikely), or, most likely, the majority of those early votes came from the same location, causing the voting ring safeguards [2] to kick in. [1] http://news.ycombinator.com/item?id=1782058 http://news.ycombinator.com/item?id=1782058 [2] http://news.ycombinator.com/item?id=3894695 http://news.ycombinator.com/item?id=3894695

dazbradbury 14y ago
Unfortunately, I know this wasn't the case - I didn't provide the link to anyone in our office, which has it's own IP, and I know they weren't aware of the HN post until afterwards. I also wouldn't publicly use this as an example if I knew I had been rigging the votes! So maybe it was just a case of HNers flagging the story as it became popular, as the title was fairly link-baity? I was under the impression that flagging a story kills it rather than suppresses it, but regardless, if that's the case then it makes sense. Edit: One comment in your example link by ColinWright seems to state 2 or more "flags" can cause this behaviour: http://news.ycombinator.com/item?id=3893207 http://news.ycombinator.com/item?id=3893207 If that's the case, it's probably best people don't know about it, as used maliciously it would be fairly disruptive.
- jtheory 14y ago
  > Unfortunately, I know this wasn't the case You can't know -- just because it wasn't in your office doesn't mean it didn't happen. One of the first readers to see it may have mass emailed his/her colleagues who all read/upvoted when they got into work in the morning, for example....

pg 14y ago

You set off the voting ring detector.

dazbradbury 14y ago
Thanks for responding, and I don't mean to waste your time, but that seems like a bug. We have a single ip, that 4 people can use, and none of them knew of the hn post until after the post was demoted. In fact, I don't think any of them have a hn account! On top of this, I didn't share the link with anyone, and the votes appeared to be totally organic. Our target market is not the hn crowd, and this subsequent post was merely out of curiosity, so I have very little to gain by lying. Edit: if you or your team wanted any more information for debugging purposes I would be happy to oblige, just let me know if I can help, though I understand if this is fairly low priority!
- jQueryIsAwesome 14y ago
  It maybe set off the vote ring detector because your costumers seem to be located all around London. So it may be possible that some of them shared the submission with other London users or that because they know your company they up-vote it; making it look like it was ringed but it was just selection bias. Anyway this is a tricky problem; because at the end of the day intent is a fundamental part of vote rings and that can be really hard to see by algorithms alone.
flipside 14y ago
Can you share anything about how you define a voting ring?
- zitterbewegung 14y ago
  Probably doing so might tip off the people who try to game HN so I don't think its a good idea to share that kind of information.
  - deleted 14y ago
    [deleted]

TallboyOne 14y ago

What I want to know is how I get tons of HN traffic daily months after my post is off the front page.

evilduck 14y ago
Search engine results. The comments are indexed and are often niche enough to dominate certain search terms.
MaysonL 14y ago
Probably it's search generated...

supersaiyan 14y ago

Can I ask what js framework/proj. you are using to graph the data?

jpalacios 14y ago
looks like highcharts JS

JeremyMorgan 14y ago

Because you're on the 15th page by then?

zerostar07 14y ago

You 're all entrepreneurs (or wannapreneurs). Why doesn't one of you create a service that will employ mechanical turks as seed to bootstrap a new website by using it and providing honest feedback? I know i would pay for that. Being on the frontpage in HN will not guarantee seed userbase; it's more of an ego boost.