I am not sure when this feature was turned on but it appears that Google has added IMAP service to Gmail. I logged into my main Gmail account to change the POP setting and noticed that the screen was different. I suspect that this is a stealth upgrade. Google normally has some king of “New features” thing in the upper right hand corner of the page. They do this for Google Docs and Spreadsheets as well. There was nothing on the main page to indicate something was new.
IMAP appears to be enabled by default. The Gmail team has provided configuration instructions for the most popular mail clients. I use OS-X Mail.app to read my Gmail ( I use the browser elsewhere ). Under POP I had to suffer with my mail being archived whenever it was downloaded. With IMAP I will be able to keep my Mail.app view and web view synchronized.
One thing I did notice is that my list of labels appeared as IMAP folders in Mail.app and the list of IMAP folders including the Spam bucket. I think this is a great idea and is what the user community would expect. I think Google has once again upped the ante when it comes to email.
(via Island in the Net)