This is according to a client of mine in the home based business industry. Now don't get me wrong, I am not saying that Google (or Yahoo!) organic listings don't bring you quality traffic, or amazing conversion, I am just pointing out that a search engine that many would consider dead (as far as traffic goes) still can get your quality traffic that converts.
The conversion rate this last week was 95% for this particular client of mine on MSN. My point in bringing it up here on this blog, is to make sure people know that their search engine optimization campaigns should include MSN.
You will not get a ton of traffic from MSN, even for some pretty big words, but the traffic you get is quality and could help your overall organic conversion rate. If you are selling a high end (high ticket) item, that could be a huge loss of revenue if you are not optimizing with MSN in mind.