Why does Google Search use redirects instead of direct links?

Question

All Google Search results are a redirect link like this: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=19&ved=0CHUQFjAIOAo&url=http%3A%2F%2Fwebapps.stackexchange.com%2F&ei=jNV0T4a0EYTw0gGkxsX_Ag&usg=AFQjCNFUKoDTez5xOnJZaRkn0OLZIclKtQ&sig2=siQi9Rk3h_zHwaNC2n_MMg

Why does Google do this?

Answer 1

One of the reasons is so they can do click tracking on what link you clicked, on there search results page. This allows them to detect and optimize there search results.

For example if they noticed everyone that searches for "batman" only ever selects the 2,3,6,7 links, they could remove the 1,4,5 links as they are obviously bad results for this search word.

Also you should take a look at Google's search history. I can tell you are logged in from this link and that your search history is being logged. This will give you a good indication of the information that Google collects when you click this link.

Answer 2

This is a method which Google has been using to track what links their users click. When you click on that long link, Google knows it.

If you want to turn it off, see the answers to this question.