Twitter’s growth is still accelerating. The service has reached 125 million registered users, up from 105 million almost two months ago.

When the company said it had 105,779,710 million registered users on April 14 at its first developer conference, Chirp, in San Francisco, it said it was growing by roughly 300,000 accounts a day. Today, Twitter spokesperson Sean Garrett said the company had 125 million accounts, meaning it’s been growing at an average pace of about 340,000 new registered users a day since Chirp.

Twitter’s chief operating officer, Dick Costolo, said two days ago in New York that the company was seeing 190 million unique visitors a month to, up from 180 million visitors in April. But visitors are different from active users, which is what competitor Facebook tracks. Garrett said the company favored measuring visitors partly because it is moving toward an information consumption model, where it’s less important if a person actually tweets or shares content. That’s in line with Twitter’s advertising model, which will show sponsored tweets whether or not a person is a registered user of the site.

Facebook, by contrast, can only display ads to a person if they’re logged into the social network. That, of course, could change over the next few years as the company has the pieces in place to launch a distributed advertising network if it desires to do so. (The company hasn’t said anything official on that front.)

Facebook has also been engaged in some statistical finagling. It used to report status updates a day, counting about 60 million a day back in February. But with the advent of the new “like” button, it’s begun to prefer tracking total interactions and shares. Facebook users share about 25 billion pieces of content each month, or about 50 per user every month if you assume the service has 500 million active monthly users.

Twitter users, in comparison, post 65 million updates a day or about 2 billion a month.

The company has been stepping up its user on-boarding efforts, doing aggressive A/B testing on its homepage (see below).

Today, the company also launched a series of videos instructing newbies on how to use the service at a YouTube channel: