we know there are a lot of webmasters using the traffic exchnage websites to promote their sites to the other webmasters to get massive traffic.so in your mind,Do traffic exchange site is useful for page rank or just alexa rank to our websites?
IMO traffic exchange is good for building up alexa rank, i have my serious doubts google is going to count the traffic when it is computing PR (anyways PR is dead for now without an update for 8 months), google might count it if the traffic were to come from organic searches.