Hi,

I've tried some funny URL in Google Profiles which are "blocked" :

http://www.google.com/s2/profiles/g
http://www.google.com/s2/profiles/a
http://www.google.com/s2/profiles/z

Others are enough only "Not found" :

http://www.google.com/s2/profiles/d
http://www.google.com/s2/profiles/o

Do you have an idea about what's happened for these URL ?

Good pick, Fr.
Maybe g, a and z are used as Google Account test ID.

http://www.gstatic.com/s2/profiles/images/blocked-96.png
http://www.gstatic.com/s2/profiles/images/404-96.png