AI is extremely useful for web companies since they collect terabytes of historical user behavior and want to make predictions about how users will behave in the future. In particular, machine learning is very widely used within Google, Facebook, LinkedIn, etc. to do search ranking, anti-fraud, ad targeting, spam filtering, friend recommendations, you name it. Other AI sub-fields like planning are used in shipping and route optimization.

I'm at a 4-person startup and AI is the core of what we do. My e-mail is on my profile if you (or others) are interested.