Started writing out a little happy dance over Michael Mann's defamation suit winning a preliminary battle and then saw Eli's already covered it several hours ago, so go read. I'll just add four points:
1. It's especially good because one motion by the naughty parties was an anti-SLAPP motion, intended to shut down, quickly, those frivolous SLAPP cases that are brought to oppress free speech. Among other things, a successful anti-SLAPP motion usually changes the normal American rule and allows the defendant to recover attorney fees from the suing plaintiff.* Barring a successful appeal, Mann is now free of that monetary threat.
2. It's good news for Mann, but mind the footnote following the statement (p. 15) "The Court must, at this stage, find the evidence indicates that the CEI Defendants' statements are not pure opinion but statements based on provably false facts." The footnote reads in full, "The Court does view this as a very close case." IOW, it could go the other way at trial.
3. A difficult issue even if Mann wins may be proving damages to Mann's reputation, in that it's difficult for statements by disreputable liars to have much effect on the reputation of honest people. OTOH, Mann's claim for intentional infliction of emotional distress also gets to proceed, and that can get him damage awards, especially if the judge is angry with the defendant over the defamation and looking for a way to make the defendant provide compensation.
4. I think this case and the Supreme's actions on California Prop. 8 are good examples of why the law is like The Force, to be used for good or for evil. Anti-SLAPP motions were meant to be used for good, to help the little people who are sued by giant corporations for defamation when they tell city councils to vote down bad developments. Obviously, they can be twisted. Conversely, the modern version of legal standing that shut down Prop. 8 and brought gay marriage back to California was expanded by rightwingers to violate environmental laws by making it difficult for citizens to enforce the laws on their own. Standing then came around to catch the rightwingers on their own petards. This time.
*I don't actually know the law in Washington DC where this case was brought, but I'd be pretty surprised if it's different from anti-SLAPP done elsewhere, and it uses California law as a model which does allow fee recovery.