Hashtag inventor Chris Messina started his new year with a new job at Uber.

Messina worked at Google goog for six years until August 2013. Monday was his first day on Uber’s Developer Platform team as the company’s first Developer Experience Lead. He writes in a Medium post that he’ll be working to improve Uber’s existing apps and develop new ones to build upon or integrate with the development platform.

He describes Uber as a “network facilitator” and wants to work toward a future in which the Internet is not solely experienced on the screen but is something that’s “present in and connects the everyday things that are all around us,” a shift that he believes is inevitable.

Uber has been at the center of much controversy since its inception. In the past, the company has been accused of lying to customers regarding the quality of drivers’ background checks and has been criticized for treating drivers unfairly.

Messina addresses Uber’s controversial nature in his post and says he’s “vigilant” about it, but adds that we shouldn’t let “nostalgia” deter us from improvement. He writes, “the world in which we live is not efficient, not thoroughly humane, not sufficiently accessible, somewhat inequitable, and certainly not done being built.”

Messina first proposed using a hashtag, or pound symbol, to his Twitter followers back in 2007.

He told the Wall Street Journal that Twitter rejected the idea at first, telling him, “These things are for nerds. They’re never going to catch on.” The company was obviously very wrong, and now hashtags are basically unavoidable. Twitter even has a guide on how to use them.