LinkedIn co-founder Reid Hoffman announced today that he’s making a big bet on Change.org, the site for social justice petitions. Hoffman is leading a $30 million round, with other investors including big names like Bill Gates and Y Combinator president Sam Altman.

“Change.org, the global hub for collective action, is a crucial democratizing force in this era of growing civic participation,” wrote Reid Hoffman on LinkedIn. “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.”

The organization was founded in 2007 by CEO Ben Rattray. Since then, almost 200 million people around the world have used the site to raise awareness for a range of causes, including human rights, the environment, education and health issues.

Rattray wrote a post about the global mission. “We are in the early stages of the development of a new, more participatory form of democracy, and in order to realize the potential that technology has to transform civic engagement, we need to build tools that give us wider reach and enable deeper involvement,” he said.

The proverbial tongue-in-cheek in Silicon Valley is that people want to build things that “change the world.” This one actually does.

But they’re not a nonprofit, they’re a business. They make money by charging companies and nonprofits to sponsor petitions, which they say brought in $20 million in revenue per year. Unfortunately, that wasn’t enough to keep them from laying off 30 percent of their staff in September. They have since introduced crowdfunding, which has generated “millions of dollars of revenue.”

This isn’t the first time that Hoffman bet on the Change.org team. In 2014, he was part of a large group of high-profile investors, including Richard Branson, Ashton Kutcher and Twitter co-founder Ev Williams.

They’ve raised more than $42 million dating back to 2012.