A: I think that bloggers have a bit of power, but only to an extent. Some of the well established, long running, influential bloggers do have some power. How many authors have become widely read because of Maryse? Or because of Aestas? New authors, and authors that are just reaching their audience, can be made by being featured on a big blog. Independent authors also rely on blogs to spread word of their new books. Bloggers like these have built a huge following and have integrity with their readers.
On the other hand, when it comes to mainstream authors, I don't think that blogs wield too much power. For example, I might be absolutely giddy to receive an ARC for a Jeanine Frost, Ilona Andrews or Patricia Briggs book, but is my opinion as a blogger going to make or break the book? Absolutely not. Why? Because established authors don't need blogs to drive their books' sales.
As a reader, I find that I follow bloggers that I know like the same types of books that I like. Bloggers that share the same interests as I do do have a certain power over which books I buy. If it wasn't for Aestas' review of Bad Romeo, I would have never bought it.
But let's face it - there are a million book blogs out there. They all have some readership and influence some people. Although blogs are obviously helpful to many authors, I think that some authors give too much credit to blogs and not enough to their writing.