I am sure that every SEO has once dreamed of prying into a competitor’s (or a client’s competitor) traffic stats. Now there is no accurate way of doing this and most of the scripts I’ve used thus far have been pretty misleading, however one does stand tall above all other traffic estimators.
Not sure who made this script but Traffic Estimate has made a pretty good traffic estimation script for us traffic metric junkies to use. I have used Spyfu for the past few months to track what my competitors were doing (even though the accuracy of the data is debatable) I could never really get a good estimation of their web traffic. Until now, Traffic Estimate seems to nails the spot when it comes to obsessive compulsive traffic monitoring of competitor’s website.
I practically check it everyday now, on a magnitude of different websites I visit, just to take a glimpse of what type of traffic certain websites are receiving. Now with that being said, I must warn you that the data is not that accurate, you may need to multiply the traffic estimate by about three. Either way, this is as close as you can get to stalking your competitors, for free atleast.
Check out http://www.trafficestimate.com/ and start spying now.