Microsoft’s Bing search market share grew again worldwide during the month of February.

The software giant’s “decision engine” now has a global share of 4.37% compared to Google’s 89.94% of the global search engine market. Although Bing still trails behind Google, the search engine has managed to increase its market-share by nearly a whole percentage point since December. Global statistics firm StatCounter said that Bing overtook Yahoo share in January and increased its lead in February.

“It is significant that Bing overtook Yahoo! globally for the first time on a monthly basis but it remains a tough battle to claw back Google’s market share,” commented Aodhan Cullen, CEO, StatCounter. “Although Google dipped below the 90% mark in February worldwide for the first time since August 2009 it shows little sign of losing its global dominance any time soon.”

Steve Ballmer, Microsoft CEO, recently compared Bing to a weed. “We bet on Bing and are growing like a weed in that business. So I feel pretty good about the bets,” said Ballmer. The comparison of Bing to a weed is a rather accurate one. Microsoft has shown it isn’t afraid to ensure Bing is everywhere. The software giant has pushed two minute video demos of Bing on iPhones, released Bing iPhone games and ensured Bing is making its way to the latest Toyota line of cars. The constant iteration and product updates also keeps Bing high in the mind-share of users. Microsoft appears to have followed Google’s approach with a number of UI and feature enhancements in previous months.

Google isn’t happy about Bing’s approach however. Google kicked off a search engine war of words earlier this month after Search Engine Land posted a broad investigation into what Google claims is Bing cheating search results. Amit Singhal, a Google Fellow who works on the company’s search engine ranking algorithm, claimed that Bing was simply copying Google’s results. Google allegedly caught Microsoft’s copying by creating a “Bing Sting.” The search giant created one-time code that would manually rank a page for a certain term and create around 100 synthetic searches searches that hardly anyone would ever enter into Google. The searches returned little or no results on Google or Bing but Google created a special honeypot page to show at the top of each synthetic results page. The result? Bing started listing the random queries only a few weeks after Google began listing them.

Microsoft was quick to deny Google’s claims with a blog post entitled “Thoughts on search quality.” Microsoft’s Harry Shum simply shrugged off Google’s claims as part of over 1,000 different signals and features in Bing’s ranking algorithm. Google wasn’t happy leaving it at just that though. Amit Singhal published a Google company blog post entitled “Microsoft’s Bing uses Google search results—and denies it.” The blog post outlines much of the original report from Search Engine Land but also called Bing’s search results stale and a “cheap imitation” of Google results. Microsoft and Google employees also traded jibes over Twitter regarding the findings.

Microsoft’s search alliance with Yahoo appears to be paying off too. Marin Software, a paid search marketing platform provider, and Razorfish, an interactive marketing and technology company, unveiled the results of an exclusive study in January conducted to analyze the impact of the Search Alliance on paid search campaign performance. The results showed that the Search Alliance has resulted in improved traffic quality for advertisers and increased its share of paid search impressions by 4% and its share of clicks by 2%.

Bing also passed Wikipedia on Compete’s list of the top 50 websites for December 2010. Bing took the sixth spot with 79.8 million unique visitors. Compete reported that Bing closed the year with a 105.36 percent increase in unique visitors — the largest yearly growth among the top 50 sites.