Traffic Estimates for Other's Sites

Guessing how much traffic someone else's web site gets is inexact at best. Using more than one free tool can give rough numbers, though they'll vary widely and not always be accurate. Here are a few I've tried:

Compete

Makes pretty graphs, and uses relatively standard numbers (e.g., unique vistors, page views per visit, etc.). I haven't tried their premium services but imagine they're simlar to their free offerings, only more in depth and specific.

Quantcast

Their profiles break down some good demographic information as well as basic numbers like visits. They seem to give some insight in to who visits, not just how many.

Alexa

The grand daddy of such sites, Alexa's rankings have been what has pushed some sites into the popular consciousness. They also include useful information like how fast a site is compared to the net at large.

trafficestimate.com

Their numbers seem slightly inflated, but the month by month bar graphs are some of the simplest I've ever seen.

comScore - not free

Offers nothing free for an individual site, but seem widely well regarded. Is almost for the web what the Nielsen ratings are for TV (though Nielsen will hate me saying that since I think they offer web ratings too).