Reviews are like magazine and newspaper articles...once you write them for a site and submit them, they become the sole property of the site. Most review sites on the web have the disclaimer that reviews become the sole property of the website. Whether that would hold up in court or not, is anyone's guess.

A similar situation happened when Letterman left NBC...who owned the material - Dave or NBC? Dave obviously got to keep some of his bits (Top Ten List), but others had to go(Dave could no longer call Calvert Deforest "Larry 'Bud' Melman")