SimilarSites - Easily find more sites like those you like.
AlternativeTo - AlternativeTo lets you find apps and software for Windows, Mac, Linux, iPhone, iPad, Android, Android Tablets, Web Apps, Online, Windows Tablets and more by recommending alternatives to apps you already know.
Sites Like - Siteslike opened it's doors to the public on the 4th of december in 2008, since that time...
Product Hunt - A website that lets users share and discover new products
FreeSitesLike - FreeSitesLike is a user contributed website dedicated to offering its visitors with plenty of options to a specific website.
moreofit.com - Moreofit is the first (and best) website similarity search engine.