How traffic changed from PR0 to PR4

More than a month ago, Colnect's PageRank has changed to PR4. Now's the time for some statistics taken directly from Google Analytics deployed on Colnect.

Comparing the last 2 weeks with the 2 weeks before the change show 25% more traffic from Google. But what's more interesting is that there's 68% more traffic from Live and 58% more from Yahoo. So the PageRank probably did make a difference but is Yahoo and Live taking their information from Google? Perhaps it was vice versa and I just never stumbled upon tools to test my ranking with these search engines due to the lesser amount of traffic they bring.