How much text should I be highlighting?
When making a post with the Passle button, don’t highlight more than a couple of sentences or a small paragraph. You really only want to draw attention to one significant point in the article, and use this as a base for your own arguments and views.
It’s also good etiquette to put “…” if you want to shorten part of the text you’ve captured, so your readers are aware that there has been some editing of any quoted text.
See also: How much to write in a Passle post?