How often has this happened with you that you visited a site and after that which ever site you went to, you started seeing the ads of the site you visited? If you know anything about web and browsers you know it is the cookies that were planted by the site. Cookies are nothing but small text files containing some information about the client machine. Often harmless and mostly used by sites to give you a tailor-made experience whenever you visit the site next, but very annoying in some cases like the one I just mentioned. Browsers give you facility to clear either the entire browsing history (which includes visited sites, cookies, cache, form data etc.) or individual items and you can delete all the cookies in one go. But if you want to see which sites have planted cookies in your machine and clear only the ones you want to, read on. Chrome: Click on the 'Wrench Menu'. Click on 'Show Advanced Settings'. Under 'Privacy', click on 'Content Settings...