Eric DeFriez of Google:
For a while now, many of you have been asking for a better way to access data to build apps that integrate with Gmail. While IMAP is great at what it was designed for (connecting email clients to email servers in a standard way), it wasn’t really designed to do all of the cool things that you have been working on, which is why this week at Google I/O, we’re launching the beta of the new Gmail API.
Google’s Gmail API documentation says that it “should not be used to replace IMAP for full-fledged email client access”, but my question is “for how long?”. If a greater number of people use IMAP clients to access Gmail, fewer ads are seen. If fewer people use IMAP, Google has a shrinking reason to keep supporting it.