These links gave you a list of some of the big names behind the ongoing cloud adoption and industry transformation:
This is one of the links I found on the Openstack mailing list that give us a small inside view to this problem: Cloud tools survey
The most interesting results are listed in point # 4 and 5.
4. Which clouds do you use (choose all that are appropriate)? Amazon: 47.4% Rackspace: 36.8% HP Cloud: 21.1% Go Grid: 0% Linode: 31.6% Softlayer: 0% Joyent: 0% Azure: 5.3% Google: 10.5% Private Cloud: 42.1% Other responses included AppFog, OrionVM (Australian provider), KT UCloud Biz (Korean provider), eNoCloud and Physical Servers. 5. How many cloud based servers do you manage (not physical servers)? 1-10: 45.5% 11-50: 27.3% 50-200: 9.1% 200-1000: 18.2% 1000+: 0% A lot of fairly large deployments – many of them appear to be private clouds (who responded via the OpenStack list).