Book marketing guru's all speak highly of getting book reviews, even to the tune of sending out 500 or so books to get the word out.
I've found the top 500 blogs in my subject area (I write nonfiction) and am spending a couple of months going to each one and asking if they'd like to do a review and a giveaway. Some don't reply. Some say they've got too many books beside their bed, or they don't do reviews. But about 1 in 6 request a copy for review. (I'll tabulate later just how many come through. Some need reminders.)
Nobody acts like I'm bothering them. It's a win/win and they're grateful for getting a free book on a subject area they're passionate about. And some of these blogs get major traffic. One that reviewed my book yesterday gets 80,000 visitors per month, has 250 incoming links, an Alexa rank of 94,000 and 900+ subscribed RSS readers.
Again, I'll tabulate results later (like how many came through with reviews and how many of my books actually sold as a result), but it seems at this point to be a good campaign.
btw, I do take the time to read some posts on each blog, and read the "About" section so that I can see if we're indeed a match and I can personalize my request to each one. I think it's better to take a slow, personal approach than just try to see how many blogs I can hit in a day. A couple of the bloggers mentioned how much they appreciated that I took the time to check out their blog before suggesting a review.
Has anyone else had success/failures in getting reviews from bloggers?