It's easily automated. It's still a nice thing to do for your users. Also just because you're a fortune 500 doesn't mean you shouldn't take steps to build relationships with your users. The same attitude works in reverse. You have freedom of choice with the service you use.
I think the email is the first part of building the relationship. Sure the first email is automated, but you can't call it building a relationship unless there's a real human being on that end trying to understand what's going wrong.
Agreed. Trying to pass automated emails as personal never works. It is, however, a step in the right direction. Knowing that a dev is looking after the API users is somewhat comforting.
I wouldn't be surprised if a small or new company emailed me about nearing the API limit. They're trying to build a relationship.
But a Fortune 500 like Yahoo or Google? They couldn't care less about someone trying to use their free API. You're just one of thousands to them.