A person who constantly Googles or uses Wikipedia (or other internet resources) to self diagnose their illness based on symptoms they've been experiencing.
Kaley is a Wiki-chondriac. She wakes up with a slight headache after a night of drinking. She immediately sources Wikipedia where she finds that there are several common causes including:
"tension, migraines, eye strain, dehydration, low blood sugar, hyper mastication and sinusitis." She also finds that there are life-threatening conditions such as "meningitis, encephalitis, cerebral aneurysms, extremely high blood pressure, and brain tumors" associated with headaches. She quickly jumps to the conclusion that she's dying of a brain tumor and needs medical assistance rather than a Tylenol and some water for what is a really a bad hangover.