Yes, on three of our sites we have discussion boards that have produced a good number of indexed pages over the years that pull good traffic. Two are hyphenated domains and one is not. The non-hyphenated domain is doing fine; the other two are down over 95% in pages indexed.
I don't believe this is a penalty; a problem for sure, but right now Iím not ready to start believing Google is penalizing sites because there is a hyphen in the domain.
I do believe we are seeing a real fundamental shift in how these guys are data mining, and its going to result in some changes.