I agree Google is ranked as the best and most powerful and vastly used search engine in most of the countries. May be that is the reason that almost all people make Google the focus of their optimisation efforts and put Yahoo as second. This is probably the right mentality, as these two search engines get the vast majority of all searches and have the greatest potential for delivering traffic to your site. However, MSN is third in line and can still deliver a considerable amount of traffic. Moreover, it is one of the easiest search engines to get new sites listed in, so if you have a new site with low pagerank, targeting MSN is a worthwhile strategy. Below are a couple of tips to help you get listed in MSN:
MSN places a lot of weight to on-page content. Make sure you mention your keywords in the title and page description and aim for a keyword density of around 3% to make the most of on-page factors.
Unlike Google, MSN will give you credit for almost every link you get. It doesn’t matter if these are bad quality links or reciprocal links – the more the merrier. Getting loads of links in a short space of time can give a nice boost to your MSN listings: its quantity not quality of links that counts for MSN. Of course, these strategies may do more harm than good in other search engines so be careful!