Zazzy - Design and sell your own 3D printed jewelry
DISQUS - Disqus is a global comment system that improves discussion on websites and connects conversations across the web.
Back Market - the refurbished (super) market
Commento - A fast, bloat-free comments system to foster discussion on your website
FeedbackSpark - FeedbackSpark is in-product micro survey tool that helps product teams to remove guesswork from product development. Harness the voice of customer to drive product success.
utterances - A lightweight comments widget built on GitHub issues.