kontxt

<a href="https://kontxt.io/" rel="nofollow ugc">Kontxt</a> adds an interactive layer to the web. Enrich websites with highlights, comments, polls, @mentions to page parts, deep links, and control who and how visitors can interact with your sites.
Add highlights to your website and make comments and polls for yourself and others that have shareable deep links that scroll directly to them. @Mention people to send an email notification with a deep link. Use the side bar pop-over to let you and your visitors efficiently view all the activity on the page. Navigate quickly between highlights locally with next and previous arrow buttons, and globally with the small placeholders that span the left side of the page. Enable these features just for yourself to emphasize content, draw attention, and add additional context to page parts, or let your users respond to your highlights, comments, and polls, or let them make their own highlights, and interact with other visitors annotations, too.
The Kontxt for WordPress plugin lets site owners and developers easily add Kontxt to their websites, which can be used along side or in place of the default WordPress comment system.
<h3>Support</h3>
E-mail info@kontxt.io if you need help or have any questions.

Kontxt – Inline Engagement System: Highlights, Comments, Polls, Sharing

Kontxt is the web's leading interactive platform. Use Kontxt to increase engagement, boost traffic, keep readers, and build your audience.

Pedro

LINER In-Site makes your website ‘highlight-able’. 
Visitors will be able to highlight on your website and share highlighted link with others.
Major features in LINER In-Site includes: 
* Highlight your blog or web page. 
* Share highlighted web page to your friends via Facebook, Twitter, and Permalink 
PS: Please subscribe your email on our website(https://connect.getliner.com/api/in-site) and receive further updates and changes.

LINER In-Site

LINER helps you highlight sentences on the web. Highlight your favorite texts.

Kontxt – Inline Engagement System: Highlights, Comments, Polls, Sharing vs LINER In-Site