A month back, Scott Beale wrote about a shirt created by Improv Everywhere; the shirt allegedly infringed a trademark of Best Buy. On Tuesday, December 11, Beale got a cease and desist letter from a Best Buy lawyer (or shell script). But by Wednesday December 12, not only did Best Buy acknowledge the first amendment rights of bloggers (their word choice, not mine) they actually sincerely apologized.
Similarly, on Friday, December 14, T-mobile stopped delivering customers' SMSes to or from twitter.com. In arrogant letters, "Executive" customer service representatives claimed that *not only* is twitter an unapproved third party application, but any attempt to cancel one's service over the issue will result in a $200 charge. But by Sunday, the issue was mysteriously resolved.
Both corporations back-pedaled; Beale and Twitter both graciously called the events a misunderstanding. Not the power dynamic you'd expect, is it?