Brief history: Blizzard makes a DMCA complaint against Bnetd, resulting in the temporary downing of the Bnetd website and the Bnetd server code no longer being available for download. EFF decides to represent Bnetd, and they exchange a few letters back and forth. On Friday, Blizzard files suit.
The most interesting thing about the legal claim is that they make no claims under the DMCA. You should recall the distinction between regular copyright law (which prohibits making copies of original works of authorship) and the DMCA (which prohibits making, using or distributing devices intended to circumvent anti-copying protection measures on copyrighted works). Even though Blizzard claimed in their letters that the fact that the Bnetd server doesn't implement CD-checking (which is impossible for them, since it's a secret algorithm known only to Blizzard) makes it a DMCA-violating circumvention device, they didn't raise the claim in the complaint they filed with the court.
- that Bnetd copied code from Blizzard and incorporated it into Bnetd (how this was accomplished isn't stated; since Blizzard does not make their source code available, presumably the Bnetd people would have to break into Blizzard headquarters).
- that Bnetd posted screenshots of Blizzard games to their website (this should be deemed fair use by the courts).
- that Bnetd is engaging in an unauthorized "public performance" of Blizzard's copyrighted material by running a Bnetd server. At least, that's how I parse paragraph 28. Perhaps they're instead making a claim about something that was posted on the Bnetd website, but paras. 28 and 30 read together imply that Blizzard is arguing that anyone who makes software to interoperate with other software over the internet is making a public performance. This would allow Microsoft to shut down anyone who made .NET software, for example, because it will invariably involve a lot of transmission of information that Microsoft can claim is copyrighted.
- that Bnetd infringes on Blizzard's trademark (an identifier for goods or services that are sold) for "BATTLE.NET" by calling their software "Bnetd", because, after all, "Bnetd" is essentially identical to "BATTLE.NET" (coming next: the makers of the elm email client sue the makers of pine, emacs sues eine [who sues zwei], Unix sues GNU... chaos). That is, people who use Bnetd may be confused because the name is so similar to Battle.net that they think they are actually using a Blizzard product.
People who are offended at Blizzard attacking its fans and customers may want to consider Warlords Battlecry 1 and 2 instead of Warcraft 3. The original Battlecry is selling for $10 these days and is quite good.