What are some alternatives?
When comparing SideComments.js and Juntoo, you can also consider the following products
Nofanity - Nofanity removes swear words from YouTube videos
Genius Beta - Annotate the Internet
Carnival - Carnival Mobile offers a suite of Mobile Marketing Engagement and Analytical Tools. Get the best in creative, location-based mobile marketing.
FundaMine - Get Medium style annotations on your site
Hidy - Auto hide unwanted social comments (FB, Instagram)
Sidenotes - Annotate the web.