It’s official, Microsoft and Yahoo have formed a search alliance. What this means is that “search ad inventory from Yahoo!, Microsoft, and their respective partners will be combined into a new unified search marketplace, giving advertisers of all sizes access to a combined audience of nearly 577 million searchers worldwide.” Video after the break.

Our aim is a high quality transition of advertisers and partners in at least the US prior to the 2010 holiday season. However, we may wait until 2011 if we determine this will be more effective.

[via SA]