An excellent example of overzealous prosecution over internet blog/article comments is the Reason magazine 'woodchipper' debacle. This WSJ article is a good place to begin reading, although Popehat did a lot of great work, and Reason covered the story a little bit after the gag orders and subpoenas had died down.

https://www.wsj.com/amp/articles/reason-magazine-subpoenaed-...