MSN Search Hiring: Gobble, Gobble, Gobble

I check out the SEMPO job board from time to time to see who's hiring for SEM-related positions. MSN Search has ~150 open req's listed, which is 10X more than any other company.

Why is it that Google isn't resorting to mass req postings on SEMPO despite having stratospherically high hiring goals? My guess is Google is the place to be, even in Redmond.