well as posted by Bimmer late last month Sendo is suing Microsoft, but at the time the details of why they were suing were sealed. They have been released by the folks over at the Register now. Here is a little excerpt:

The claim alleges - are you ready to start counting? - misappropriation of trade secrets, common law misappropriation, conversion, unfair competition, fraud, breach of fiduciary duty, two counts of negligent misrepresentation, two counts of breach of contract, fraudulent inducement and tortious interference. Phew.

The article can be found here

El Diablo