From a twitter tweet of the ENWorld owner "Morrus" :
"Eeek. WotC has its lawyers send us letters about member posts now? I miss The Rouse!"
WTF? Hopefully he posts the letter. How stupid is WOTC? ENWorld is like the last bastion of supporters outside their own message boards. Maybe they want the entire message board content of the internet for their own as well.
I would suspect, if I had to guess, that it has something to do with people posting shit with proprietary WOTC stuff in it, like power cards or stat blocks of something they think they own.
Yet another milestone in the PR debacle that is WOTC
EDIT: I want to see the letter so we can see how far-reaching in scope they are shooting for. Assuming its some perceived Intellectual Property violation, their delusional megalomaniacal actions may affect blogs as well.
EDIT THE SECOND: From Morrus on ENWorld:
"I'll not point anything out directly, but there was a large amount of WotC's IP (direct from the books) posted. It has been dealt with."
You'd think a quick email to Morrus, without getting the Legal Dept. involved would have settled it? I'm sure he would have taken it down with a quick email saying "Hey man, there are parts of our books copied and pasted on your forum. Please take it down."
WTF? Like killing a fly with a sawed-off. The Corpo-Borg Assimilation is apparently complete.