Microsoft's Bing online search service gained usage share in the United States for the ninth straight month in February, according to market researchers at Hitwise and comScore. Google still dominates the market, with about 68 percent of all searches. But Bing now accounts for over 10 percent of searches and, unlike with Google, its share is actually rising. (In second place, Yahoo controls about 15.7 percent of the market.)

Bing's gains, while still modest, have at least been steady since the service launched with a $100 million ad campaign in June 2009. Many wondered whether Bing would drop off once the money ran out, but that hasn't happened.

And Microsoft, of course, has some interesting deals in the works to bolster Bing's popularity. In addition to the blockbuster Yahoo partnership, which will see Bing jump into second place for traditional desktop-based searches, Microsoft is also partnering with a variety of mobile companies to get Bing installed as the default search engine on smartphones.

In the latest such deal, Motorola announced this week that it will preinstall Bing as the default search engine on its Android-powered phones. (Interestingly, Google makes the Android OS.) The first of these phones will launch in China sometime this quarter, Motorola says.

Bing will also be the default search engine on the new generation of Windows Phones that will ship beginning in September. On those devices, users will be able to access a custom Bing application via a dedicated Search button.