Similar Sites addon is a browser extension, plugin or addon for Google Chrome and Mozilla Firefox and Opera, also called a Browser Helper Object for Internet Explorer. The Similar Sites addon provides similar sites while using your favorite browser. In the right corner is a addon enabled which displays a numerous of sites related to the site your are currently viewing. SimilarSites improves your browsing experience with Sites like the ones you’re looking for. When we tested adware and bundled installers on our test machines we found this SimilarSites addon was added to the extension list and enabled. This means it is promoted during the installation process and you got it installed when you did not ask for it to install.
It is advised to always read the Terms and Agreements before installing software on your computer. Do never click too fast thru the installation process [Next] button of software as you will agree to software you might not want to install. If the installer offers a Advanced or Custom option button, click it to find out if there is any other malicious software offered and installed during the installation process.