I've been noticing recently that when I Google something, and then click on the link, my browser does not immediately show the target web site in the "address" bar but some complicated Google address.
So today I thought I would look more closely. I turned the "browser log" on in Firefox, searched for Arduino, and selected the top hit (the Arduino.cc site). Even though the mouse-over window appears to indicate that clicking will take you to arduino.cc, this is what actually happens:
[14:22:34.708] GET https://www.google.com.au/client_204?&bi... [HTTP/1.1 204 No Content 179ms] [14:22:35.322] GET https://www.google.com.au/csi?v=3&s=web&... [HTTP/1.1 204 No Content 160ms] -- [14:22:43.185] GET http://www.google.com.au/url?sa=t&rct=j... [HTTP/1.1 200 OK 218ms] [14:22:43.581] GET http://www.arduino.cc/ [HTTP/1.1 200 OK 1297ms]
That's 3 calls to Google sites (presumably HTTP redirects) before the target site is fed to the browser. I've been noticing before that if you want to help someone out (eg. find the Arduino web site) you can no longer Google it, and then just copy the link from the Google page. For example, for Arduino you get this:
(Partly obscured in case it has my personal information there, which wouldn't surprise me).
So now you actually have to follow the link, watch various addresses appear and disappear, and then you can copy the link from the targeted site.
So is Bing any better? Well, marginally:
[14:24:48.819] GET http://www.bing.com/fd/ls/GLinkPing.aspx? ...[undefined 83ms] [14:24:48.902] GET http://www.arduino.cc/ [HTTP/1.1 200 OK 1215ms]
That's just one redirect rather than three.
So the moral is, Google (and Bing) know who you are (after all they know your IP address). And they also know, after you did a search, which link(s) - if any - you followed. Just imagine what they could do with that information!