Facebook of Sex — Trademark Infringement or Parody?

Facebook has sued Various, Inc., the owner of Penthouse, adultfriendfinder.com and other adult-themed websites, in the United States District Court for the Northern District of California, for trademark infringement based upon Various’ creation of website called Facebook of Sex with the URL: facebookofsex.com.  Various has defended the name and the website saying, among other things, that it is a parody permissible under the First Amendment of the United States Constitution.  The case is in its nascent stages and no decisions have been rendered.  So, what do you think:  infringement or parody?