how to find traffic of any website and visitors they are getting?

is it easy to find how much traffic others website is getting? recently i came across a interesting question in yahoo answer which says "How can i find a website traffic source?" very interesting is in it? well this question might really does not interests you until your are a blogger, website admin or some sort of person associated with website...

every blogger or web admin has a internal fantasy to spy and know the web traffic stats of other website or his rival web-blog every webmaster always be prying on other sites and constantly monitoring and trying to improve his website traffic no matter what it takes he tries all kind of SEO, keyword stuffing, spamming, link exchange what not just to improve traffic...

like wise i am no different like others i too wanted to know the secrets of traffic source, SEO and other tricks done by other bloggers and webmasters to improve my website but it is not that easy to get traffic stats such as unique visitors, page views, traffic source unless and until you own the site but alteast there are certain ways by which you can get 70% of the information which is enough to know overall stats of any website.

though there are many websites such as google trends, statbrain, compete, Quantcast etc i will personally use two tools to get the basic information of website

Alexa:
Alexa stats are not to believable as any one can trick alexa by installing their tool bar and visiting there site themselves couple of 100 times will greatly change the alexa traffic rank but i like one feature in alexa that helps me in finding the traffic source of any website though stats are not accurate at least it gives the major traffic source of any website just got to alexa.com enter your website address and click on "Click stream" tab as shown in below pic this should give you the traffic source of any website you want though not accurate but is helpful.


Google Ad Planner:
this is one of the tool that i use to get average traffic source of certain websites, averaga no of visitors, page views, unique visitors etc


--> just go to Google ad planner website
--> Click on the tab "Begin Research" type URL and hit enter

there are other stats widgets such as site meter, amung.us and other that may be website is using you even also get stats from such tools if you know any other tricks do share with us...