Last fall, Rackspace went through a major outage that released many of its customers from their long-term contracts. Then, earlier this year, Tumblr founder David Karp publicly voiced his discontent with Rackspace and the company cut its prices by 80 percent in order to keep his business. Karp didn't take the offer, telling us its cheaper for startups to load up on redundant servers than to depend on Rackspace's 100 percent up-time promise.