For those of you who remember, think what could have happened if SOPA and PIPA had been in force when we had the TamelaJ/Victorias mess.

One of the big Constitutional issues (this from friends who specialize in Constitutional Law) is that it violates the innocent until proven guilty, trial by a jury of your peers, and right to face your accuser clauses.

Someone making a claim doesn't have to have hard evidence.  They just need a "reasonable suspicion".  The site is immediately blocked for a period of six months while the claim is investigated.  If the investigation finds violations, the feds procede with the case but the original claimant does not have to appear to testify as to how or why they came to make the claim.