From the article:
The operators of these indexing sites appear surprised at the MPAA's decision to sue, as they have yet to receive any notification.
"Funny, they didn't email me," Gary from ISOHunt said. "I'm not too concerned because we deal with copyright requests everyday, some of them from studios MPAA represents."
"Justin" from TorrentSpy echoed Gary's skepticism. "I guess I will learn more when I see what they have filed exactly. [I'm] not sure why they are suing when we comply with DMCA requests but I guess we will learn more down the road."