Sure, but the only book blogs I regularly visit rather than just stumble on via google are Wertzone and OF Blog, and usually not for suggestions. I'm looking for a second take on a book I've already read, to add more depth to it. To see what I missed or a different perspective. When I get new book suggestions its usually incidental, like some aspect of the book I really liked being compared to another book I haven't read. I don't much care if a book, even a non-SF/F one, is dated. I tend to enjoy the reminders of prior popular fads or idioms. As you say, blogs focus on new releases, often pre-release, but most have archives that pop up on a google search for that book, and most reviewers mix in older favorites or classics or special requests with the new releases. Since I usually arrive by google rather than seeking that blog, it's not a problem.
I suppose blogs like the one I co-run are a bit different in focus from the so-called "new shiny" crowd, but it certainly is neat seeing how people arrive at the blogs I maintain (the other main one, Gogol's Overcoat, has a steady flow of traffic from people, presumably students, looking for reviews of specific stories by Flannery O'Connor, Zora Neale Hurston, and William Faulkner). Sometimes that reference-based searching is overlooked by those who want to be the first to cover a book or author. Nice to be reminded of it.
Je suis méchant.