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Twitter has a limit of 140 characters to fit in a regular SMS (the rest 20 are used for the username). From https://en.wikipedia.org/wiki/Short_Message_Service

by zuck9 11y ago

Twitter has a limit of 140 characters to fit in a regular SMS (the rest 20 are used for the username). From https://en.wikipedia.org/wiki/Short_Message_Service https://en.wikipedia.org/wiki/Short_Message_Service > Short messages can be encoded using a variety of alphabets: the default GSM 7-bit alphabet, the 8-bit data alphabet, and the 16-bit UCS-2 alphabet. Depending on which alphabet the subscriber has configured in the handset, this leads to the maximum individual short message sizes of 160 7-bit characters, 140 8-bit characters, or 70 16-bit characters.

richardwhiuk 11y ago
That's not true. Firstly, a single tweet doesn't necessarily fit into a single SMS (as the Twitter limit is per character, whereas an SMS is limited per byte). Secondly, an SMS is limited to 140 bytes, which is 160 7 bit 'characters', or 140 8 bit 'characters' or 70 16 bit 'characters' (in UCS 2, normally).
- mikeash 11y ago
  It was true. Twitter heavily emphasized SMS back when it was new. The 140-thingy limit hasn't been about SMS for a while now, and has just transitioned into a weird artificial limitation that's become part of what Twitter is. But that is how it started out.
- deleted 11y ago
  [deleted]
moron4hire 11y ago
That might be the origin, but that is not the current implementation. For example, URLs only ever count as 23 letters, because they always get shortened using Twitter's own t.co shortener. BUT they still display in their original form, so unless they are de-referencing the shortened URL on the fly, they have to be storing what the user typed and a pre-processed form of the text are being stored. That's a lot more than 140 ASCII characters.
- mikeash 11y ago
  What's really fun is that URLs always count as 23 characters even if they're shorter. For example, I had a tweet about Apple's Keynote.app fail to send the other day, because Twitter thought "Keynote.app" was a URL and "shortened" it such that my tweet exceeded the length limit afterwards. Fun times.
  - moron4hire 11y ago
    Yeah, it's not good. I think Twitter would do well to not hurt users with things like that. Use the restraint of UI to keep people's posts small. It's difficult to type a screed into a single-line textbox. But get rid of any actual character limit at all.

by zuck9 11y ago

richardwhiuk 11y ago

That's not true. Firstly, a single tweet doesn't necessarily fit into a single SMS (as the Twitter limit is per character, whereas an SMS is limited per byte). Secondly, an SMS is limited to 140 bytes, which is 160 7 bit 'characters', or 140 8 bit 'characters' or 70 16 bit 'characters' (in UCS 2, normally).

mikeash 11y ago
It was true. Twitter heavily emphasized SMS back when it was new. The 140-thingy limit hasn't been about SMS for a while now, and has just transitioned into a weird artificial limitation that's become part of what Twitter is. But that is how it started out.
deleted 11y ago
[deleted]

moron4hire 11y ago

That might be the origin, but that is not the current implementation. For example, URLs only ever count as 23 letters, because they always get shortened using Twitter's own t.co shortener. BUT they still display in their original form, so unless they are de-referencing the shortened URL on the fly, they have to be storing what the user typed and a pre-processed form of the text are being stored. That's a lot more than 140 ASCII characters.

mikeash 11y ago
What's really fun is that URLs always count as 23 characters even if they're shorter. For example, I had a tweet about Apple's Keynote.app fail to send the other day, because Twitter thought "Keynote.app" was a URL and "shortened" it such that my tweet exceeded the length limit afterwards. Fun times.
- moron4hire 11y ago
  Yeah, it's not good. I think Twitter would do well to not hurt users with things like that. Use the restraint of UI to keep people's posts small. It's difficult to type a screed into a single-line textbox. But get rid of any actual character limit at all.