Microsoft's fledgling Windows Live Search replacement—Bing—is off to a fast start: According to web analytics provider StatCounter, the service surpassed Yahoo! Search last week to take the number-two spot behind Google. This placement is likely temporary, but Microsoft can be heartened that its efforts to promote the improved and renamed service have gotten people's attention.

"It remains to be seen if Bing falls away after the initial novelty and promotion," StatCounter CEO Aodhan Cullen said. "But at first sight it looks like Microsoft is on to a winner."

According to StatCounter, Bing snagged 15.6 percent of US search usage share, "leapfrogging" Yahoo! Search, which accounted for 10.32 percent. Google, meanwhile, was at about 72 percent usage share, although Google's share had fallen steadily since Bing was publicly released.

The worldwide numbers are more mixed for Bing: Google accounted for almost 88 percent of web searches (down from 90 percent when Bing launched), compared with 5.56 percent for Bing and 5.17 percent for Yahoo! But even this can be explained away as Microsoft has yet to launch all of Bing's features in various countries around the world. (Great Britain and Australia, for example, receive only a small subset of the new services' features.)

To promote Bing, Microsoft has started a $100 million ad campaign aimed at web, print, and TV. The most interesting aspect of this campaign is a unique one-hour web-based infomercial that will air live this evening on Hulu.com at 8pm EDT. Users who view the "Bing-a-thon" infomercial live receive credits to watch TV shows and movies on Hulu.com later without commercial interruption. Microsoft has also arranged a promotion with NBC's Late Show and The Philanthropist, the latter of which is a new show that starts later this month.

Bing needs all the help it can get. Although the service itself is excellent and in many ways superior to Google's ubiquitous search service, Microsoft has never been able to make its previous search services, Windows Live Search and MSN Search, successful.

You can find out more about Bing in my Bing Beta Review on the SuperSite for Windows. (Part 1 is now available.)