Bing is on the Offensive trying to gain some Ground against the might of Google. Although Google is far and away the market Leader Bing still has a huge amount of traffic that is not something you want to forget.
Bing Currently gets 4 Billion Searches per week
4,000,000,000 per Week
57,142,857 per day
2,380,952 per hour
39,682 per minute
661 per second
So if you are looking to use SEO for your Website then you need to ensure you rank in Bing as well as the other search engines as the numbers go to show there is huge potential here.