Bing and Yahoo are merging which should happen in the next year, however through speaking with the USA delegates, there seems to be much more usage in the USA than in the UK
Bing has a cool tool showing a score to any inbound links you have. Their thinking is that it will allow you to see which are good links and which are not. I suppose this is an attempt to stop people building poor links as they will see they are not really worth the effort. However you will only be able to download 1000 results so better for newer sites than older ones.
From hearing all the stuff that Bing is doing it obviously has some really cool features. The question is if Google has dominated the market or if there is space for another? You can have the coolest site in the world but if only a small amount of people use it, it doesn't matter how good it is, which interestingly is the same issues most sites have.
It seems that for both google and bing, matching your keywords to your www address is a good way to go.
It is much better to have a larger number of unique websites linking to your websites as opposed to the number of total links pointing to the site.
One of the biggest take aways is that the difference between good and bad is a very small margin.
Links still rule, match keywords to domains and google and bing are quite similar.
Don't chase the search engines as the search engines are chasing the user experience so chase the user experience.