Windows Live Hotmail has a new trick up its sleeve--one that's aimed directly at getting users with e-mail accounts on other services to use it exclusively, even if they keep that address.

That trick, which begins rolling out to Hotmail users today, lets them add accounts from other Web mail services that can be read and sent from within the Hotmail Web client.

As Hotmail's group program manager Dick Craddock writes on the Inside Windows Live blog, this functionality is something that's long been available in the Outlook software client, but not on the Web. Craddock also notes that more than 30 million Hotmail registrations have taken place where users provided another service's e-mail address to get in the door, and that these will now show up as an account you can link up to within the Web client.

Once a user has set up their outside account within Hotmail, they can read and search through messages, as well as respond to them from that address. The feature uses POP, meaning that unlike IMAP (which may, or may not be available through the other e-mail provider), whatever changes are made in Hotmail don't make an impact on things like read count or organization back on the source account.

Microsoft is billing the new send from account feature as a way to make use of Hotmail's specialty features, which includes spam filtering, media sharing, and the mass deletion and reorganization tool it's dubbed as "sweep"--all without having to leave whatever account you're already using.

Hotmail will now let you use an e-mail address from another provider to read and send from that address.