I did a test of a site that gets 122K unique visitors a month according to Google Analytics. The following sites said it got: 49K - Compete.com 70K - Quantcast.com 127K - Traffic Estimate.com (pretty darn good) 105K - SeoApp.net (also not bad) I would be curious if anyone else has done a similar test on these or other sites and what their results were.
And how about the actual traffic got from Analytics or Statcounter and compare to those traffic estimators.. I agree with SEOApp and Traffic Estimate are way much better among them..
I would say all of them are not that accurate ever. However, if I have to choose one among them I would choose Quantcast.com over other ones. I have experienced most of them and found Quantcast is more reliable than others.
None are accurate unless you're analyzing a site that has their tracking code on them. Otherwise they are typically WAY off the actual results and barely usable.
Not luck, but they do function a little different. It also differs what they count as a visitor, when the tracking code/script is loaded during the normal page load and several similar variables. Of course they should be closer to each other, such a large difference can't really be justified but again, it really depends on how they are constructed, how you load/call them and so on and so forth.
Fair question. The answer truthfully, I don't care that much. But I do buy sites occasionally and if there were a site that provided an accurate measure of another site's traffic it would be useful. What usually happens is you go poking all over the place for clues about the sites performance, you get info from the seller, some of which is accurate, some of which isn't, and you are generally in the dark. This isn't just about traffic but backlinks, revenue, etc. That's really the only time when I really care. Sometimes it is nice to see how the competitors are doing, but again, no big deal.
I think 90% of all Guaranteed companies might have fake traffic. I am sure they use some kind of PHP software that might route HTTP to get requests through a massive list of anonymous proxy servers or IP addresses. Did you check if the hit came from one of the anonymous or fake IP addresses the script stores in a database ? I am sure half of the traffic might be sent by the fake traffic PHP script which is unique and shows up as unique in the stats too.
I have personally studied this and I can tell you that none are accurate really... They can give you a rough idea to the amount of traffic a site gets (high, medium, or low) but an exact number is impossible for all. I personally own a bunch of sites and some of my sites with lower alexa rank actually have significantly higher alexa rank, further proving inaccuracies.