Angstro marks the fourth company that Google has acquired this month. It bought Slide, a social games developer; Jambool, a company that makes a platform for managing online payment for virtual goods sold on gaming and social-networking sites; andLike.com, a visual shopping engine.

Angstro’s Rohit Khare (who I know from conferences) in his blogging about the acquisition wrote: “”While our work here may be done, the struggle for open, interoperable social networks is still only just beginning, and I’m looking forward to working on that in my new role at Google.” I don’t know what Rohit’s role is going to be at Google, but he’s a good person to have anywhere, and especially if he’s going to push Google toward the goodness of a single, open, non-discriminatory Internet.