When Yahoo, Inc. (NASDAQ: YHOO) featured a two-week test that saw it use competitor Google, Inc.'s (NASDAQ: GOOG) text advertising, the move was done with moxie. Yahoo! spent a lot of time and money developing its Project Panama text advertising system only to bring in Google's market-leading system as an outsourced solution. What was the deal? Well, the deal was Yahoo!'s attempt at making a takeover by Microsoft Corp. (NASDAQ: MSFT) as hard as possible.

That two-week test was completed a few weeks ago, and now rumors are surfacing that Yahoo! may enter into an agreement with Google to carry the search leader's advertising once again. This partnership would make it harder for Microsoft to acquire Yahoo! (something that's waiting in the wings), while providing Yahoo! with some decent cash flow. It seems almost every partner of Google's, insofar as text advertising, ends up doing quite well.

While Microsoft still has not said anything almost a week after its proposed offer for Yahoo! expired, the end of this summer could see a major shift in the online advertising landscape. Either Microsoft will be successful in acquiring Yahoo! through a proxy fight or an upped-price offer, or Google and Yahoo! will have a partnership that would give Google even more power in the online advertising world -- where it's already the king of the hill by far. Break out the fake fingernails, 'cause you may be chewing on them if you have any holdings in any of the three companies