Almost a year after the initial details of the interoperability of the two IM networks surfaced, Windows Live Messenger (FKA MSN Messenger) and Yahoo Messenger are now officially connected!

After months of hard work from both sides and lots of feedback from users during a lengthy BETA period, the integration is now final! Yahoo users can now have Live Messenger contacts on their list, and vice versa.

This feature is available to users of either Windows Live Messenger 8.0 or Yahoo Messenger 8.0. To start adding your Yahoo friends to your Messenger list, read our quick guide to adding Yahoo contacts.

This is certainly great news for users of either IM service. A large percentage of the users on either network have contacts on another IM network, and this move allows a massive number of people to communicate across the two services.

Other than text messaging, you can also send a select set of emoticons and smileys that are common between the two networks and also send your contact a nudge/buzz. The upcoming Windows Live Messenger 8.1 is not expected to increase any of these functionalities further (e.g custom emoticons, voice chat, VoIP, etc), but this basic interoperability is a huge step in itself.

Another great feature common to both Live Messenger and Yahoo (which was first implemented by Yahoo Messenger a long time ago) is offline messaging. Users will be able to leave offline messages for each other, which will be delivered the next time the recipient logs on.

Overall, this huge development is certain to strengthen the position of both services in the IM realm, going against other competitors such as AIM, Skype and Google Talk.

For more information on Live Messenger 8, visit our special Windows Live Messenger page.