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The content being a dynamic webpage where if you change a single byte (ads, page logo, anything) the hash changes? Try to load any webpage twice and see if you

The content being a dynamic webpage where if you change a single byte (ads, page logo, anything) the hash changes? Try to load any webpage twice and see if you can get exactly the same bits. And just imagine how much of the internet FB would have to periodically hash, and what impact it would have on those sites too.

kerkeslager 7y ago
That's a feature not a bug. Not only is it a feature, it's the feature. That's the entire point. It doesn't have to be the entire page that's hashed, only the content being liked. Facebook would probably never implement this, because their entire business model relies on them being a trusted authority, so trustless architectures would actively undermine them. In general, if you see my name above a post, you can assume that the only thing I want Facebook to do is sell all their assets, give the money to charity, and shut down. :)
- close04 7y ago
  > It doesn't have to be the entire page that's hashed, only the content being liked. I think there's a disconnect here... The page to which your posted link points is the content. Whatever loads when clicking the link is the content you hash, with ads, scripts, the main body, the comments, the everythings. If I link to the front page of HN it's guaranteed it will never ever have any likes. If I link to an article that says something like "posted 6 minutes ago" then every minute the page changes. A FB robot loads the link, receives some data (the full page), hashes that, attaches it to your "Like". Then rehashes periodically. But every time someone clicks the same link they load slightly different content. Simply because something on that page changes. A new comment in that page, an evolving story where the site puts updates, a live blog, or a different ad loaded on the page, which are all valid reasons for a page to change. They would all invalidate the like. So what happens next time? FB robot loads page, gets data, hashes, new hash doesn't match. Your Like is removed because the page changed. You might as well remove the Like button for anything linking outside of FB. Educating users is an option, big warning that the content behind the link may change but let's be honest, most people will be oblivious to the implications.
  - kerkeslager 7y ago
    > The page to which your posted link points is the content. I disagree, the page is not the content of the page. I hear where you're coming from though: what you're saying is a widely-accepted approximation because "semantic HTML" is not semantic, so we don't have a way to get the actual content from an HTML page. This is by design: lots of big websites have a vested interest in making it impossible to separate their content from their presentation. But I don't think future implementations have to be bound by previous bad decisions.

kerkeslager 7y ago

That's a feature not a bug. Not only is it a feature, it's the feature. That's the entire point. It doesn't have to be the entire page that's hashed, only the content being liked. Facebook would probably never implement this, because their entire business model relies on them being a trusted authority, so trustless architectures would actively undermine them. In general, if you see my name above a post, you can assume that the only thing I want Facebook to do is sell all their assets, give the money to charity, and shut down. :)

close04 7y ago
> It doesn't have to be the entire page that's hashed, only the content being liked. I think there's a disconnect here... The page to which your posted link points is the content. Whatever loads when clicking the link is the content you hash, with ads, scripts, the main body, the comments, the everythings. If I link to the front page of HN it's guaranteed it will never ever have any likes. If I link to an article that says something like "posted 6 minutes ago" then every minute the page changes. A FB robot loads the link, receives some data (the full page), hashes that, attaches it to your "Like". Then rehashes periodically. But every time someone clicks the same link they load slightly different content. Simply because something on that page changes. A new comment in that page, an evolving story where the site puts updates, a live blog, or a different ad loaded on the page, which are all valid reasons for a page to change. They would all invalidate the like. So what happens next time? FB robot loads page, gets data, hashes, new hash doesn't match. Your Like is removed because the page changed. You might as well remove the Like button for anything linking outside of FB. Educating users is an option, big warning that the content behind the link may change but let's be honest, most people will be oblivious to the implications.
- kerkeslager 7y ago
  > The page to which your posted link points is the content. I disagree, the page is not the content of the page. I hear where you're coming from though: what you're saying is a widely-accepted approximation because "semantic HTML" is not semantic, so we don't have a way to get the actual content from an HTML page. This is by design: lots of big websites have a vested interest in making it impossible to separate their content from their presentation. But I don't think future implementations have to be bound by previous bad decisions.