Twitter formally files for IPO - seeks $1 billion

The San Francisco-based social network Twitter formally filed paperwork today with the U.S. Securities and Exchange Commission for a public offering of its shares totaling $1 billion.

The news comes just shy of a month after the company first revealed its intention to go public and less than two years after its larger peer Facebook did the same to eventual success.In an S-1 filing, the microblogging company claimed it now has, on average, more than 218 million active users per month and more than 100 million per day. That's a 44 percent increase from last year...