- UX Without User Research Is Not UX (nngroup.com)
- http://www.optimalworkshop.com
- Treejack - Content tree testing
- OptimalSort - Card sorting
- http://www.usertesting.com
- http://www.crazyegg.com - Heat maps
- https://www.optimizely.com - A/B testing
- http://fivesecondtest.com - Test the effectiveness of landing pages and CTAs
- https://usabilla.com
- http://www.hotjar.com
- http://silverbackapp.com - "Guerilla usability testing on the Mac made easy"
- http://www.invisionapp.com
- http://www.notableapp.com
- https://trackduck.com
- http://bounceapp.com
- http://bugmuncher.com
- http://bugherd.com
- https://conjure.io
- http://wake.io
- https://redpen.io
http://www.smashingmagazine.com/2014/09/16/essential-visual-feedback-tools-for-web-designers