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.
Site Rank Data - View historical rank information of websites via time series charts.
SimilarSites - Easily find more sites like those you like.
Q-Stats - Get free marketing insights for every question on Quora.
Product Hunt - A website that lets users share and discover new products
Seoxan - check seo report for any website, alexa ranking, server information, meta tags, authority, page speed and more