Microsoft will relaunch Windows Live Search under a new brand sometime early next year, says a source within the company. What we don’t know is what that new brand will be, although a few names have been thrown around. According to our source, a “final” decision has been made, but very few people inside of Microsoft are aware of it, and it could change.

Now LiveSide is saying there’s evidence the new search brand will be Kumo, which means “cloud” or “spider” in Japanese.

Why would Microsoft go through yet another rebranding effort? Live.com has a lot of different services under its umbrella (some server software, some client software) in addition to search. It’s also a burgeoning social network.

Over time, we’ve heard, Live.com will become a pure social network and personal productivity portal. You’ll go there to access email, calendar, photos, activity streams, etc. But search belongs somewhere else, and it definitely needs a fresh start.

Microsoft won’t comment on the name change, or even if there is a name change. But our sources caution us that nothing has been finalized, and the fate of Yahoo could swing this one way or another as well. So Kumo may very well be the name Microsoft is planning to use, but that decision may change.