Embed in WP or in Bb with iframe code. Free version collects results but doesn't identify user but it can still be useful for gathering overall understanding.
A collaboration between Pixar and Khan Academy - bridging math and science with animation through lessons and activities. Aimed at middle school-high school, but really, come on, this is pixar!
Chrome extension -- Creates a layer over a web page so that you can annotate, either privately or publicly to other hypothesis users, to add comments or having a discussion. Critiques, evaluations, peer review and more.