It's very possibly bots. I have written (all over the place) about this type of bot attack. Unless you're obsessive (like I am) you might not even notice it until it starts to show up in your Analytics.
Then on November 12, 2013, the same site started getting hit again. Mostly the same footprints, except that this time, they were spoofing different viewport sizes (some appearing to be mobile) even while still identifying as Windows 7 or Windows XP (NO Windows 8, interestingly) All still identifying as IE. This time, though, they're hitting the home page, and three of the taxonomy pages (but NOT any pages that were created since the 2012 attack) It's still going on right now, and having talked to a few people who experienced the first attack when I did, it seems they're experiencing the second right along with me now.
There's no practical way to ban by IP; there's tens of thousands (if not more) of them. They come from all countries (lots of Brazil, though) including the US.
As far as I can tell, it's mostly harmless, other than being a PITA for analytics. It doesn't seem to be searching for a file, or clicking on any ads, or trying to go any deeper into the site. It may be some kind of PC virus that executing tasks "under the hood" on the infected PC, and going out to sites with whatever IE is installed, but what the payoff is, I sure don't know. It'll be interesting to see if it stops in January or keeps going. The fact that I got hit the same times as a couple of others makes me think that there's some list of sites that we're on.