Twitter will reach 500 million registered users on Wednesday.

In mid-January, the site analyzed numbers from Twopcharts which suggested Twitter would reach 500 million users by February 26th. That date has now been moved up to the 22nd, as users are accelerating the pace at which they’re signing up for the microblogging service, according to Mediabistro.

Twopcharts is calculating they’ll reach this milestone at about 3:45pm ET Wednesday, February 22.

The milestone comes as Twitter rolls out a long-awaited self-serve ad platform for small businesses.

It also comes as more stats show how viable the platform is for brands. To cite one example: Twitter brand followers—by a count of 6 in 10—are either more likely to recommend many (18%) or a few (42%) brands as a result of following them, according to a study released by Chadwick Martin Bailey.  Also, the study noted, 50% of Twitter users go online more than once an hour, compared to 34% of Facebook users and 29% of overall online users.

Facebook users are slightly more likely to go online once every couple of hours (46%) than Twitter users (40%) or overall online users (45%).