I've gotten a couple comments where people asked me what "Woo" means. Normally, I just give them a link to Skepticwiki's take on the term. Orac has recently written a good post on the topic.
Sometimes, skeptics are understandably criticized for using the term to dismiss something. Personally, I tend to use it in the reverse manner: If you can dismiss something because of its illogic, then that makes it woo.
I usually give a person a chance to prove that he's not a woo: If he can answer a few simple questions, he's worthy of further consideration. If he can pass The Randi Challenge, then he will have my undivided attention.