MSN's Search Engine Beta algorithm has a lot in common with Google's and Yahoo!'s algorithms , But also has some difference with alogirithms.Recently the MSN search engine has been launched in beta version .The MSN Search Engine developed byMicrosoft developers.Achieving high search engine rankings in MSN has some similarities to the techniques already used in Google and Yahoo. As expected, the MSN algorithm has a few twists and turns for SEO professionals to navigate as well.
As with the other major search engines, MSN Search requires good relevant content, and quality incoming links featuring keyword rich link anchor text. That said, there are some differences and similarities with Yahoo and Google’s preferences. After all, all search engine algorithms, while similar in many basic ways, are unique in their requirements in other areas of search optimization.

The most important aspect of the MSN Search Beta is the need for good keyword rich content. Relevance of theme and topic appears to be very important to MSN, as it is becoming for Google optimization. There are also additional considerations for levels of on page keyword density that differ somewhat from Google. On the other hand, MSN seems to strongly dislike keyword stuffing, and will drop a site’s ranking accordingly.

Links are important to MSN, as they are important to Yahoo, and of course to the legendarily link obsessed Google algorithm. Maintaining your important keywords on the incoming and internal on site link anchor text is important. That link text definitely requires mixing and variation to appear as natural as possible when crawled by the MSN spider.Clean coding is a must with MSN Search, as its spider has a strong preference for well written code. For non-programmers or website owners with low levels of coding skills, that necessity could become a problem. If a website’s code is poorly written, it appears that MSN Search downgrades the site’s search rankings heavily.

Look at
http://www.errorforum.com/msn-search-optimization/964-msn-search-engine-beta-optimization-techniques.html
if you want to know more about MSN SEO Optimization Techniques.