"The more than 30 lines of coded material use a maddening variety of letters, numbers, dashes, and parentheses"
It's obviously a port of sendmail written in Perl.
Has that been used in the past against a patent holder??
Not that I know of. "Slander of Title" is really a real estate law concept, however, SCO made an interesting attempt to use to enforce an alleged copyright claim. In their case, it turns out they didn't actually *have* the title they were claiming was being "slandered" by Novell. However, there really didn't seem to be anything fundamentally wrong with the reasoning - the consequences of claiming you own something you don't has substantial legal history behind it. In this case, it may actually require that MPEG-LA explicitly claim they "own" part of VP8, through a patent, in order to be actionable (assuming, of course, that the claim is false).
There have been previous threats about Theora, but nothing happened. This could be FUD bluff too.
One interesting difference here is that they're going up against someone with deep pockets. If they can't find something substantive, MPEG-LA is risking a "slander of title" claim, and Google might consider making an example of them.
The actual story is here