Keyboard comedian
A person who happens to be very funny online, on forums or private conversations, but ends up being pretty boring, awkward or hard to talk to in the real world.
-I really thought we were going to have a better yesterday with Matt, he seemed like he was so clever and funny on Facebook. Turns out he was just weird and awkward in person.
-Yeah, he's a keyboard comedian.
-Yeah, he's a keyboard comedian.