Google Messenger would probably fit in to their internet strategy, think about it - Gmail, Picasa, Blogger, Adwords/Adsense are all services by them that have a searching twist, however arent really google searching.
Also with the purchase of Picasa, they also got Hello
http://hello.com/how_it_works.php which is basically an Image sharing program with an added IM service, however turn it around to make it an IM service with an added image sharing capabilities, and you've got yourself an IM service.
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