Rating: 12.52 million viewers.
The title mixes "Goth" and "Wolowitz" (Goth, the lifestyle and Wolowitz, the character in the show) and also gives a few hints on the episode's plotline.
Visual: Leonard, Penny and Sheldon are watching the animated show "Oshikuru: Demon Samurai".
This is a reference to an episode of "Two and a Half Men" ("The Salmon Under My Sweater") where the characters Jake and Charlie are collaborating on the show's theme song. These two series are both created by Chuck Lorre.
Wolowitz: Did you even read the wikiHow link I sent you on being Goth?
Howard is clearly referencing the wikiHow article known as "How to Be Goth", and is talking about this link: http://www.wikihow.com/Be-Goth