Twitter

THE MONEY TWEET: As expected, Twitter filed for its IPO today; if you're truly a masochist you can try to read the filing. If this were a tweet we'd already be out of characters, but here are a few salient points: The stock symbol will be TWTR, which people on Twitter will try to abbreviate further. The registration amount is $1 billion. Mobile's a big driver. #Music is a mobile means of discovery for artists. Oh, and "public conversations" between figures like Mario Batali and Gavin Rossdale (see image) are good for "ad engagement and reach." Will Twitter be a good buy? Will its IPO resemble that of Facebook? Hell if we know, but stay tuned. (10/3p)