Alex Macgillivray, who championed users' right to free speech as general counsel for Twitter, said today he would leave the company after four years. Known universally by his Twitter handle, Amac, Macgillivray said he would continue to advise the company on issues including trust and safety, acquisitions, and public policy. "I continue to care deeply about Twitter, the folks who work at Twitter and our tremendous users, so I'll remain close to all three," he said in a blog post.

Passing the torch. I care deeply about Twitter and our users, will continue to help while exploring other passions http://t.co/EBY6UZyN72 — Alex Macgillivray (@amac) August 30, 2013

Like many top Twitter executives, Macgillivray came to the company from Google, where he spent six years as an attorney. At Twitter, he led global battles against government and law enforcement requests to take down posts or reveal user information. His handpicked team share a belief in free speech and will continue to fight for it, he said in his farewell letter.

Under Macgillivray, Twitter created the Innovator's Patent Agreement, a contract between the company and its engineers promising that patents developed at Twitter will only be used defensively. The name for the agreement was a play on Macgillivray's favorite kind of beer, the IPA.

Vijaya Gadde, who previously managed Twitter's international and corporate legal teams, will take over as general counsel. In a tweet, she indicated that little would change under the new regime.