As Bing introduces its ubiquitous “search overload” TV ad campaign to the UK to wage its self-proclaimed David versus Goliath-esque battle with Google this week (you can watch one of the commercials here), someone has to ask the question: is Bing really capturing any search market share from Google?

Recent Hitwise numbers might lead you to believe that just might be the case. February marks the third month in a row where Bing saw an increase in its share of searches (up four percent over January to 9.7%). Google, meanwhile, saw its second consecutive month in search market share decrease – albeit a very slight drop (down one percent from January to February). comScore reported similar numbers for the month of February.

But guess what site is the fourth most visited site before visiting Bing? Google. That’s right – over four percent of Bing users first visit Google. The top three sites visited before Bing, however, make much more sense. They are MSN, at 42.7%, Facebook (remember, Bing is the default search engine on Facebook), at 4.61% and Windows Live Mail (another Microsoft property), at 4.45%. So how are Google users ending up on Bing?

Danny Sullivan at Search Engine Land offers up two logical explanations. 1) Bing buys ads on Google (Google “search engines,” and check out the paid ads), and 2) Bing, as we all know, runs a massive TV ad campaign, and commercials are known to drive search queries. The idea being a person sees a Bing commercial, and, not necessarily realizing Bing is a search engine, Googles “Bing” to see what it’s all about. If the idea of using one search engine to find another sounds strange, it shouldn’t. In fact, as Sullivan found, Google Trends reporting proves that users are clearly searching Bing by name on Google.

Before anyone starts suggesting that Google is responsible for Bing’s rise in market share, let’s put this all into perspective. Far more Google users search Yahoo and (in a bizarre twist that certainly warrants further research) Google itself.

And ultimately, perspective is what this is really all about. While Bing’s slow and steady rise in search market share is certainly worth monitoring, its numbers are still quite small compared with Google’s. Sorry, David, Goliath’s still got you beat…for now.