I'm very conscious that my tastes match up with other people's tastes in a Venn diagram - some things overlap, some don't. So when I do read blurbs (mostly when I'm stuck on choice of books) they might influence my decision, but only in a sense that I might like something this person liked, and it might be similar to something they've written. Or not. The final decision still comes down to the back cover and a few pages inside the book.