Okay, that title is a little harsh. Wikipedia is not exclusively bullshit. Wikipedia represents an astounding amount of work, much of it by well-informed people, on a dizzying array of topics. It provides almost almost unlimited free entertainment, and is often an effective starting point for an inquiry on a subject. And recently for some reason I've spent many hours wandering around the pages about prehistoric civilizations.
But you'd be a damn fool to rely on it for anything remotely controversial. Patterico has a jaw-dropping post about how Wikipedia — largely under the authority of one editor, it would seem — memory-holed the entire post about convicted bomber Brett Kimberlin.
I'm a firm believer in reading a wide array of sources and adjusting one's skepticism and bias-detection level accordingly. But it's hard to adjust for bias when a resource decides to handle a controversy by avoiding mention of it entirely.
Wikipedia's defense, perhaps a fair one, is probably this: "all right, smart-ass, compared to what?"