Annotate the web!
Komnt lets you highlight and add comments to any text on any page on the web! See the Chrome extension here
This is useful esp. when you want to bookmark a page but you care about only a certain paragraph of it. If your friend has Komnt installed too, you can even share specific snippets with them!
But if you just want the script:
Require the dist file in your HTML:
<script src='dist/komnt.js'></script>window.onload = function () {
var komnt = new Komnt();
komnt.enable();
};