PitchWall - Browse new startups, and submit your mobile app/games startup's beta page here.
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.
Product Hunt - A website that lets users share and discover new products
Top Similar Sites - Top Similar Sites helps you find similar, alternative or related sites to any website instantly.
TechStorey - Discover a new Tech Business at the click of a button
The Startup Pitch - A place for startups to share themselves with the world.