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!
CThruView Transparent Image Viewer - CThruView is a free transparent image viewer that allows mouse clicks to go through the image.
userinput.io - Get on-demand feedback for your app, website or idea. Learn how to improve by hearing real opinions.
PixelPerfect - Allows developers to put a semi-transparent image overlay over the top of the developed HTML and...
Userbrain - Easy, fast, and affordable user testing for websites and prototypes.
Osiva - Osiva" is an acronym that stands for "Overly Simple Image Viewing