This question already has an answer here:

NOTE: in this question I am interested in discovering the actual method used by Google to track me -in my particular case- and in exploring eventual ways to circumvent it. This is completely different from the question is Google spying on us all. That question is asking "if" Google is tracking users and goes on to talk if that is a correct/acceptable behavior or not.

ok, here is the situation:

I started noticing the same type of ads following me in various sites: in particular a couple of ads regarding "2000+ Chinese women online" and about "meet Thai girls"...

Now, I find that really strange since my Firefox is set to delete cookies when I exit, and Chrome is always in "incognito" mode. I also tried manually delete all offline content, but same result. Another idea: I tried to reboot my internet modem and I got a different public IP.. but still same result.

  • As a tests I went on www.linuxquestions.org with different browsers:

    • with Firefox I get those ads.
    • with Chrome I get the same ads.
    • with Tor browser (tor is an anonimity network) I get DIFFERENT ads, about Linux and computers/technology.
    • with my other laptop, using Internet Explorer, same Thai/Chinese ads.

How do you think is Google managing to follow me?

PS: I have an idea but I would like to hear your opinions first..

marked as duplicate by AviD Oct 5 '13 at 23:32

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • The duplicate question (Is Google spying on all of us) asks "Is?" while this question asks "How?". So if you drill through all the answers to the "Is?" question, you will find some information about "How?" - but you do need to drill. As they were answering a somewhat different question. – LateralFractal Oct 5 '13 at 23:40
  • Do you have any active log-ins? Have you been using social media (e.g. Facebook)? Are you logged into sites? – Shule Sep 15 at 6:22
up vote 1 down vote accepted

I would try the following (while not logged in to any Google services of course):

  1. Booting from a Ubuntu CD
  2. Using a different device connected to your network (e.g. a smartphone or friends laptop).

If the ads change in both cases, it would suggest there is still something on your computer that is allowing Google to ID you. Perhaps an old installation of Google Talk? Maybe the cookies are (somehow) not being cleared?

If the ads remain the same in both cases, it would suggest that the ads are not tracking "you", but are perhaps based on IP address geolocation or some other indirect targeting method.

For extra points, you could check the IP geolocation theory further by booting from the Ubuntu CD again, and then borrowing your neighbors WiFi connection.

PS I would certainly expect different ads when using Tor - the exit node is likely to be in a different AS Number than your current IP, and that alone is very likely to produce a change in advertising.

  • (I always forgot to answer) yes, turns out that most probably the advert was based on my home location. That's why with TOR the advert was different. – user29239 Aug 23 '14 at 14:17

Google may be using Local Shared Objects (a/k/a "Flash cookies").

For further reading, try this research article from Carnegie Mellon: A Survey of the Use of Adobe Flash Local Shared Objects to Respawn HTTP Cookies [2011]

You can check if Chrome/Firefox is protecting you against this class of attack by examining the results of Evercookie injection: http://samy.pl/evercookie/