The Twitter developer conference, Chirp, is going on today in San Francisco. Here some of the highlights so far: This morning, Biz Stone shared the latest Twitter stats: it now has 105,779,710 registered users, and is adding 30

0,000 a day. The service gets 180 million unique visitors a month and 75 percent its traffic comes from outside of Twitter.

The microblogging service is experiencing 1500 percent yearly growth and handles 600 million searches daily. Twitter has grown from 25 employees to 175 in the last 12 months.

Twitter also announced today a further step in location with “Points of Interest,” which shows where a tweet originates as well as all tweets coming from a specific location. Twitter hopes that this service will complement check-in apps like Gowalla and Foursquare.

Twitter’s in the same position vis-à-vis these companies that Facebook is against Twitter, so absorbing their functionalities makes a lot of sense, if not a lot of goodwill.

The conference comes at an odd time for Twitter developers, as there’s the growing sense that they will begin to be squeezed out of the ecosystem in the coming months. At least if the chirps that followed Fred Wilson’s talk trend true.

Twitter’s founders tried to quell that unrest while presenting at Chirp. Twitter co-founder Ev Williams assured the audience that its recent purchase of the iPhone client Tweetie and the launch of its own Blackberry app were to make the user experience better. At the same time, the language is changing.

Twitter the company is indeed growing up.

By Mark Alvarez