Via Hacker News — Updated YC Company Hosting Stats. A Ruby script was used to extract out all the startups that Y Combinator invested in, get their IP addresses, and then do a WHOIS to find out who owns the IP block. Interesting result:

SliceHost: 14
SoftLayer: 14
Amazon (on EC2): 13
Rackspace: 4
ThePlanet: 3
GoDaddy: 3
ServerBeach: 2
Pair Networks: 2
…

Then [...]