[qeorge]

Key point is that it has to fit in 1 SMS message, that's where the whole 140 character thing comes from.

[joshu]

Tweets already diverge from what will fit in an SMS. For example, 140 chars of unicode won't fit.

[jmhodges]

We go by bytes, not chars.

[chaosmachine]

That's incorrect, Twitter goes by characters. I actually wrote an app to exploit this loophole:

http://tweetcompressor.com/

[briansmith]

It only has to fit in a single SMS message if the tweet is being consumed over SMS. There's no reason to do link shortening in other user interfaces.

[fredBuddemeyer]

yes but is it worth the illegibility and extra step of shortening? how many of those sms recipients make use of the link by retying it in a browser? if there is much of a use case why not have special handling for it?

[Kilimanjaro]

I would like to know the percentage of tweets sent as SMS.

[spazmaster]

Also SMS fits 160 chars, not 140.

[barredo]

20 chars were reserved for twitter username

[blasdel]

160 7-bit characters.

Twitter usernames are 15, the ": " takes another two, and three are reserved for future sigil retardation.

[papachito]

140 doesn't include the user name, the app name and probably some more info.