Today I discovered Traffic Faker, a service you can subscribe to that will generate a list of URLs and then send a robot out to plant your URL in those websites' referral logs, making it look like you visited the sites.
There's nothing illegal about it, of course, but the point is to deceive website owners into visiting your site. To which I say: What putzes! Both the company offering this service and the users of it -- putzes all!
Update: Maybe I should have titled this 'Referral Spam.'