Alternato - NOTE: Not available in English.
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.
Aventrix - Aventrix is a website that helps you discover new and fun activities.
Product Hunt - A website that lets users share and discover new products
Slant.co - Slant is a collaboratively edited resource that helps you quickly make decisions.
Alternative.me - Welcome to alternative.me, the source of better software alternatives. Finding suitable software was never easier.