Not in the UK it isn't; the libel laws there are heavily skewed in favour of the claimant. It's why so many celebrities choose to have libel trials at London High Court if at all possible. Last.fm operates from London, so it's definitely an option for them.
Of course, then you're in the whole other deeply problematic waters of international law, and what ability UK courts have to enforce judgements on TechCrunch, but such moves aren't entirely without precedent.
Of course, then you're in the whole other deeply problematic waters of international law, and what ability UK courts have to enforce judgements on TechCrunch, but such moves aren't entirely without precedent.