This is the question posed over at Hey Lady! Whatcha Readin’? today. And a very interesting question it is too :)
Blogging has changed my reading in fairly subtle ways, I think. The most obvious thing is that my wishlist and Mt TBR have increased greatly as I've seen books reviewed and then tried to Mooch them. I'd imagine that this is the case for most book bloggers. Of course, I'm on The Project now so am avoiding the acquisition of books (and I'm doing not bad although I'm not perfect) but my little wishbook is rapidly filling a small notebook.
I've found, since I've been reviewing books (first on BookCrossing, then also LibraryThing, now also here) that I read more actively. Instead of just passivly letting the words wash over me, I'm judging the writing and watching to see if I'm enjoying it. Yes, I still sometimes read quite mindlessly but I do tend to have one eye on my review as I read.
The other change that blogging has wrought is the challenges. I used to read books in the (rough) order in which they entered by home. Today I have a challenge shelf and read from that. If it's ever empty (like that's going to happen any time soon!) I'll go back to my former method. The challenge shelf is a kind of fast-track for the books and I'll also put books there that other people have asked for when I'm done with them or that I have a burning desire to read and therefore don't want to put on Mt TBR. I like my new system and it does appear to be working for me.
The only negative I can see is that reading blogs takes me away from reading books. Sometimes, when I'm tired and not having a good day, it's so much easier to surf through some blogs instead of schooling myself to settle down with my book. I did this last night. Sure, I had fun but would my time have been better spent with my book? Maybe. But I think it's all a question of balance.