I had a similar experience when Dyn.com suspended my DNS hosting after a complaint from Amazon about a "phishing" link on my site (it was actually a legitimate Amazon affiliate link). My site was inaccessible while I scrambled to move my DNS entries elsewhere. Even though I have a premium account with Dyn, I was never given any sort of notification beforehand, and it took 5 days of pestering for them to finally reinstate it. Meanwhile, all I got from Amazon was a half-hearted apology from their affiliate customer service rep.

Really, who needs SOPA when companies can shut down websites just like that?