LinkedIn founder Reid Hoffman and Bill Gates team up for a $30 million investment in petition site Change.org

LinkedIn cofounder Reid Hoffman is leading a $30 million investment in Change.org, the for-profit "social change platform" that's best known as a site for activists to post petitions to the public.

Hoffman revealed that he'll be leading the round in a post to LinkedIn, with Fortune reporting that Microsoft cofounder Bill Gates and Y Combinator President Sam Altman will also be participating.

All three tech leaders actually participated in the company's last $24 million investment round back in late 2014. Other existing Change.org investors include Richard Branson, Ashton Kutcher, and the rapper Nas.

In his post, Hoffman refers to Change.org as "a crucial democratizing force," elaborating that "its users and petition starters hold powerful interests accountable." Currently, Change.org has 180 million users.

"It helps enable a world where you don't need to hire a lobbyist to have real impact on the issues and policies that matter to you," writes Hoffman.

The petitions on the site have ranged from the serious, like rallying to save an "exceptional" student from deportation, to the silly, like calling on McDonalds to bring back a retired chicken nugget dipping sauce. The site has inpsired legislative action, too, as when a Change.org petition resulted in new laws protecting the rights of sexual assault victims.

This investment comes less than a year after Change.org had to lay off 30% of its staff, reportedly affecting over 100 employees.

Change.org CEO Ben Rattray tells Fortune that the company generated $20 million in revenue in 2016, and will be pursuing its more recent strategy of letting petition signers contribute funds to a campaign, with the company taking a cut. Similarly, Change.org will be focusing on letting users pay to promote their petitions on the site.