T.K. Davs of Filmjerk has posted an editorial on the repercussions of taking action against spoilers.While I respect T.K. for his informative site, I must respectfully disagree on a key point.
Reviews and other such materials contain plot details, yes. But if authors/writers/screenwriters etc did not want their material reviewed and publicized in this way, they would not make their work available early. This is why OotP has not been released early to the press. When an author decides that he wants to keep his book secret until it debuts, and there shall be no reviews, he has the right to make that decision - the work is still his intellectual property. What havoc it wreaks regarding popularity of his/her book is another matter.
JKR has reached a pinnacle of popularity where she can afford to keep as much secrecy about her books as she likes. She did not have that reign when SS came out, and there were reviews galore. The bottom line is that reviews and such will not disappear, and these proceedings will not set a major precedent, because to get publicity, things have to be reviewed. The cases where authors will choose to shield their work will be when they either don't want or need the extra publicity that comes with that. Few can say they are in that position, even the most popular of Hollywood names. Very, very few can deny reviews without hurting their sales, or bump their sales by denying reviews - JKR is one of those few.
Sorry for the mini-editorial - I just felt it needed to be said.