The AI Grant fellowship has been an awesome experience so far; I highly recommend applying if you're on the fence. The grant itself is useful (and this round includes $20k of Google cloud credits!) but equally valuable is the community that Nat has curated around the project. There are a lot of great folks working on AI from all sorts of places just a Slack message away. Now that Daniel Gross (YC's AI-focused partner) is involved as well, I'd expect that community to continue to grow.
rmeertens|8 years ago