It's pretty clever really, because it's using a Google.com URL and 99.99999% of spam filters won't catch it, including Gmail's filter, because Google.com is supposed to be a "safe" URL.
The URLs come through like this:
http://www.google.to/search?hl=en&q=...kesize&btnI=I=
This causes google to search for a URL that contains girlslikesize and then tells Google that you're feeling lucky and want the first result, which takes you to the girlslikesize site.
Clever.
