Of course, you’ve always been able to forward email from most other accounts to Gmail, but the significance here is that by enabling Gmail to check your other accounts, it can grab virtually all the mail you’ve ever received in those accounts (if you haven’t taken it all off the server with a desktop client, that is – not just the messages *after* you turned on forwarding.
While this is certainly a great new feature, I must again echo the requests of many by asking: why on earth Google hasn’t joined the rest of us in the 21st century by adding IMAP access? Considering the plethora of devices consumers are using (desktops, public terminals, phones and PDAs) and the multiple ways they have already offered for accessing Gmail (web, WAP, mobile client, etc.). Is IMAP that much more difficult or expensive to implement? I realize their intention is to keep you doing email the Gmail way – labels, web ads and all – but I still say its time to grant usable access to those who need the power of desktop software and tools for their emailing needs.