Could MSN Get Sued Over Messenger P2P?

In a unanimous decision the U.S. Supreme Court has ruled that Internet file-sharing services can be sued for copyright violation if their software is intended to facilitate the illegal trading of protected material. As a result of the ruling, the case, MGM Studios v. Grokster, will be returned to the lower court for adjudication.

Gossips are already speculating whether larger firms that make P2P software, like Microsoft, may get affected by the ruling.

[Update] Some of the commentary on this from around the web:
PaidContent.org - "not a ruling against P2P"
Jupiter Research - "Grokster Ruling Won’t Stop Real Pirates"
BoingBoing - "Will Google survive Grokster"