Why does facebook change the url when I click on a

问题:

Suppose that I click on a facebook link -- once clicked, the URL is transformed to this:

http://www.facebook.com/l.php?u=http%3A%2F%2Fapple.stackexchange.com%2Fquestions%2F398%2Fhow-do-i-build-apps-to-my-jailbroken-ipad&h=uAQFM5WKt

And then I'm redirected to the URL I thought I was going to. Why does facebook do this?

回答1:

Facebook keeps track of all the links fired from its website. It saves the url you provided as link.

First it forwards you to a facebook link where it saves the url and then it redirects to the actual url.

This way facebook knows which urls are getting most hits.

FYI, Even google does it.