When Microsoft re-branded Live Search (*cough*) I mean launched a brand new search engine called Bing, they also poured in $200 million in advertising to help the self-branded "world's first decision engine" (at least if you don't count Wolfram|Alpha) get a foothold on a market that is dominated by Google.
Has it worked? Microsoft held 8.5% of the search market at this time last year, months before the world would be introduced to Bing. The new results released by comScore put Bing at 10.7%, which would mean Microsoft paid about $100 million per percentage point. Not a bad deal if they could buy their way up to the 65.4% of the market that Google owns, but of course, that's not quite possible.
How has Google done over the past year? With Microsoft working hard to attract users to Bing, Google has grown from 63% to 65.4%, which means they grew slightly more than Microsoft in the last year. So, I guess it is fair to say that Bing isn't quite bringing the competition to Google.
But in the long run, Bing is good for the web. After keeping a careful eye on it over the past seven months, the one thing I can say for Microsoft's search engine is that it's fast. Very fast. It doesn't take long for articles to be indexed by the Bing search engine, and Microsoft has added a number of bells and whistles to the search market, like real-time results and video previews.
All of which are forcing Google's hand to improve their own service via Google Caffeine, a "reboot" of the Google search engine. While Google Caffeine isn't something we'll likely notice since it doesn't change the layout or visual design of search results, it is a major upgrade to what is going on beneath the hood as Google's search engine puts more emphasis on speed and gathering results in real time.

a bit bias, you really don’t like Microsoft do you.
Most Bing users are doing so because Microsoft hijacked their browser preferences.