I wonder if they just lost many links or what? Maybe with the birth of new engines like clusty and kartoo and new google and yahoo that people are making their homepage from MSN.com to something else. Everyone who installs IE automatically has MSN as the default homepage. I didnt used to think many changed it but beginning to think most do now.
Also, I do not think their hotmail service and messenger service are as popular anymore compared to some of the new competiton like g-mail and AIM/y!-messenger.
But without a doubt Google is not gauging MSN as "popular" these days. Much like Alexa.com and www.Alexa.com
both lost a PR=7 during the July Toolbar PR (TBPR) update.
It will be interesting to see where MSN search pages (search.MSN.com PR=9) and Bcentral directory (sbd.bcentral.com PR=7) pages end up in the Google SERP's. I dont think I have seen any for a long time listed high. Only Microsoft support pages for windows and office seem to get any rankings and that I believe is microsoft.com (PR=9).