The conference is called, Science Online 2011, and this is its fifth year. Held in North Carolina (Jan. 13-15, 2011), registration opened this morning (Nov. 10, 2010). From Science Online 2011’s home page,

Anyone interested in discussing how the web and social media can be used to promote science. Once registration opens, we’ll post a list of who’s planning to participate. [emphases mine].

The registration list shows close to 300 registrants (there are more but not everyone agrees to be listed). I don’t know they are for space at this conference, you may want to sign up sooner rather than later.

You can check out their wiki for programme information as it evolves.