There were many discussions about this, and some people said that Google ignores nofollow attribute, follows the link and counts it in SERP calculation. I've added 2 links on my site using Pretty Link for wordpress. For one link I added rel nofollow, but for second link I didn't. After several hours I checked link stats and first URL which had nofollow attribute had 0 clicks. Second one, which didn't had nofollow attribute, had one click and when I checked IP, it was 188.8.131.52, which belongs to Google Inc. So that means that nofollowed links aren't followed. However, I'm not 100% sure about this, I have tried this with lots of URLs and none of nofollowed links received Google bot visit.