Everyone buys from Amazon. Or has in the past. I have been inundated with advertisements from Amazon recently every time I purchased something - all for items related to what I bought. This is just downright stupid. I bought a vacuum cleaner recently, only to get an ad via email a week later for the same base model but other variations of the unit I purchased. I cannot fathom anyone buying a vacuum cleaner just to buy another one in a week's time.

But recently they have upped their game, and even though I am aware of this being done, having it done to you always feels personal. Look at this ad I received:

That would be OK if I recently performed any searches on Amazon's site for books related to Django. Or if I did not know what the hell Django is and just received some boring unsolicited SPAM. But... In this case I have been on various sites including Google and StackOverflow performing searches related to Django as I was implementing a system with that technology. So the question is: How did Amazon know about these searches? I know of only two ways:

1. Amazon employs cross browser hacks to link your various sessions together. This basically means that you can be identified as the same user if you previously used one browser to access Amazon, and later access another site, even though you used different browsers / tabs.

2. Google / StackOverflow / some other sites I visited is selling my search history to Amazon / someone that Amazon has access to. This is the most likely scenario and also the scariest.

I know I have never searched for Django books in Amazon - and the timing of the email is no coincidence. The main take away from this is that nothing you do online is private and we have lost control of our digital privacy long ago.