Web Privacy became a hot topic when Google at the beginning of Year 2012 started tracking users online activities with Web History.
The users data collected through online tracking is often shared with third party websites and enterprises. They use this data to deliver targeted advertisement to users. If you deliberately need an item and search often about it on the internet, then there are several websites which will show you higher price for that item than usual. To get the lowest price, you should always clear your browser cookies before visiting the selling website.
Online tracking often poses risk to your privacy and anonymity. Here is a useful infographic which suggests some effective ways to ensure your online privacy and prevent online tracking.