MSNAfter using data from 3rd party vendors, MSN recently launched its own data base driven search engine. Owned by Microsoft, MSN is currently ranked #3 for search volume but has the ability to take over the #1 slot.
MSN looked to implement a big change yesterday. I'd give it another week or so to see if it sticks.
I saw a few secondary keyphrases on sites drop 8-10 positions on our sites, but the primary KW's that are supported with decent anchor text remained solid.