UserTesting.com - Usability testing has never been easier. Get videos of real people speaking their thoughts as they use websites, mobile apps, prototypes and more!
Userbrain - Easy, fast, and affordable user testing for websites and prototypes.
UserBob - Provides affordable remote user testing.
UXtweak - Online user testing and usability platform
userinput.io - Get on-demand feedback for your app, website or idea. Learn how to improve by hearing real opinions.
Validately - Validately is a user feedback platform to test demand and usability on a clickable prototype or live feature.