A web forum participant, usually using a blog, news website, or social networking platform, who contributes solely, usually without merit, basis in fact or any discretion therein, to harvest as many "thumbs-up" (or Like) responses as possible from other forum users.
The polar opposite of a Troll.
Steve: "I got 944 thumbs on Yahoo! News today!"
George: "Wow! What story?!"
Steve: "School shooting..."
George: "What was the comment?"
Steve: "'Kids today, omg, really!?!'"
George: "Nice...you're a master thumb pirate."
Steve: "Arrrrrr, where me thumbs?!?!"