I thought Microsoft was buying DoubleClick and just wrote about it the other day.  But today brings news that Google joins race to buy DoubleClick: report from MarketWatch and Search Engine Land has a local roundup too.

"..Google joins race to buy DoubleClick: report from MarketWatch reports that Google is now interested in buying DoubleClick, a provider of internet ad serving software. Now that Google is vying against Microsoft for DoubleClick, the estimates on the purchase price have jumped "beyond $2 billion." Other potential buyers include Yahoo and AOL. More discussion covered over at Techmeme.com. "

ZDNet thinks Google would buy DoubleClick just to annoy Microsoft (I doubt that).

"..Sure, Google could build its own DoubleClick-ish network, but why not just buy it for a few billion if only to annoy Microsoft. After all, Google paid $1.65 billion for YouTube, which had nearly zilch for revenue. Google could surely pay the $2 billion DoubleClick's owners want for something that resembles a real business."

But the Wall Street Journal and Valleywag thinks it's may be a rumor to drive the price - provide speculation which might benefit bankers who might be involved with a deal:

"…The Wall Street Journal reports a rumor, probably put about by bankers drumming up excitement for the online advertising company, that the Mountain View search engine has entered the bidding. If Google was to win, it would be the search giant's biggest acquisition, probably worth more than $2bn, more than was paid for Youtube. The intervention of Google would be bad news for Microsoft, which was being touted last week as the most likely acquirer; and a Google victory would trigger another round of wailing at the search engine's incipient monopoly of online advertising. But there's a reason why monopolies develop: they're often convenient; and the absorption of Doubleclick by Google would fall into that category. "

I think it makes sense for Google to buy DoubleClick - but maybe this is just a rumor after all.