Twitter

Popular micro-blogging service.

When Penny was pestering Sheldon to help her play Age of Conan, he tried to make her leave him alone. One of the ways he did this was by sending "a very emphatic Twitter." (0203).

Sheldon uses it to inform the entire university of his eating and bathroom habits (0223).

In a plot line which was dropped from The Gothowitz Deviation, Howard goes to a Goth club dressed as a vampire to meet a woman he's been following on Twitter (0303).