Statbrain is a online web stats tools that helps you guess the number of page views on any site using a combination of Alexa rank, backlink counts from Google, Yahoo and some other unknown factors.

Don’t expect it to be too accurate, but if you want a very rough estimate for any site, this could be useful.

This could be very handy for advertisers or people who are interested in measuring rough traffic on a competitor’s website.

You may also want to checkout Google Trends as they are pretty accurate.

Update: StatBrain gives an estimate about number of visits and not unique visitors or page views. If that sounds confusing, let me explain:

Mr X and Mr Y visit abc.com today. Mr X reads the front page and leaves the site while Mr Y spends more time on the site reading the front page and two other article on the site. Mr Y comes back to abc.com after a couple of hours to read another article.

Now in this scenario – the number of unique visitors is 2, the number of page views (or hits) is 5 while the number of visits is 3.

Related: Pick the Right Web Stats Program