Just to post this link wich has been advertised on a security mailing list and I find it awesome to check how many website are running under a shared hosting for example.
For example I have found out that on my old shared hosting, they are hosting 6000+ websites on the plan I had and they are hosting 24000 websites/domains on a smallest offer, that's sound incredible but that's real look yourself how some hosting are really loosers, no doubt why I had so much "MySQL server has gone away" warnings with them, check at their servers:
CRUSH (24000+ domains on this one)
CRUSH (6000+ websites on this one)
really abused to see this, this shows that bigger companies aren't always the better companies