Theoretically yes. It's a bidding process. Here in the SF bay area I only get one paid ad when I do a google search on "cluster headache", an ad for Excedrin. I refreshed my browser multiple times, clearing the cache each time, and that same ad always came up. That tells me Excedrin has paid for the keyword "cluster headache" and no one else in the SF bay area has even bid. So Excedrin might be paying a penny/month for that ad. In Des Moines, Iowa there might be a neurologist who has bid locally on "cluster headache" (you can do that), so he might be paying a nickel/month and Excedrin might be paying a dollar/month, and users in Des Moines see Excedrin's ad 20x as often as the local neuro's.
I believe there are online tools that can figure out how much you need to bid on a keyword phrase to get it to show up a certain percentage of the time. If not, you can just experiment w/ adwords and do tests to see how often your ad comes up.
Oh, heh, that's another thing about wiki, it's totally inconsistent. The little school marms can't possibly monitor the whole thing, so lots of pages slip under the radar and break all the rules. It's unfortunate that the CH page has caught some frustrated little admins' attention.
-Platy