Twitter co-founder Biz Stone announced on his blog today that he will be serving as AOL’s Social Impact Advisor.

Also announced today, the “30-Day Service Challenge,” a philanthropic program launched “to kick off the first official week of the new Huffington Post Media Group at AOL,” Arianna Huffington writes in a HuffPo post. The program will encourage people across the now-joint organization to give back to their local communities. There will also be additional coverage of companies and individual people who are doing good works.

Stone says his role at Twitter won’t change. And AllThingsD reports that Stone is getting AOL equity. Both that site and Mashable also suspect that this is a way for AOL to get some good PR after last week’s layoffs. True.