I am a tad cynical perhaps. But the kerfuffle a while back about paid blog comments both does and does not surprise me. (People are talking about it, among other places, here at Super Librarian, here at Dear Author, and here at Alison Kent's Blah Blog.) On the one hand, I am not surprised because publishing is a hard and whimsical business, like most arty fields. (Actually I think there's a lot of whimsy in corporate America too they are just better at dressing up the whimsy as other stuff.) And authors feel pressure to get the word out, to get the buzz, to get people talking. So getting people to spread the word to the online community - sure.
No, the part that surprises me is that they are paying. I am being a bit facetious, but I have participated in deals where I got a free book in exchange for talking about it online. Now of course they couldn't guarantee I would love it, and there was some self selection in my being in the places online where they talk about the kind of stuff I like. So, I guess it's easier to just pay people to talk about stuff than to offer a contest or give away too many free books when you need people to go buy your books so your numbers will look good.
And I imagine this is the end of the innocence for some people who had been taking at face value comment recommendations or Amazon or other online reviews. For me, I think it's like so many things, if it sounds like something you are interested in, then the reviews might tip you over the edge. If it doesn't speak to you, who cares what those fifty people say?