lol - you do it all the time actually. If you buy a car, the manufacturers name and emblems are all over it - thus advertising for the manufacturer.
Just noticed a module in which the vendor appears in my URL. I guess I need to be a bit more careful in the Vendors I support with my purchases. I will be removing the stamp from the URL of course. I never liked the idea of buying a new car and having the vendor stick his/her advert on the back either. If I am going to be advertising your modules in my URL, then I expect advertising revenue in return.
@Detective. I hear ya. On my modules, I have actually changed a lot of language keys and other coding to remove stuff like that. It is a pain to go through. If the vendors would be nice enough to code so that their name does not appear, it would be greatly appreciated by many. If you have a good module, it will be recommended by word of mouth a lot better than in the URL. Noone who visits my site would know who or what modzz is (if I had that module) so having that in the url does the vendor no good.
EDIT:
IMHO, the term vendor is not appropriate for those who create modules and sell them on the market. They are actually manufacturers. And in defense of module manufacturers, like any other manufacturer (Ford, Nike, Reebok, Chevy, Coca-Cola, etc), module manufacturers also have the right to display their "Branding" on what they manufacture. We can only ask nicely that mod developers do not "Brand" their modules, but they are in no way obligated to. We can only hope that they are nice and willing enough to honor our requests.
If they choose not to, then the ball is back in our courts and we have the option of taking the time to remove the branding ourselves - as long as it does not violate any conditions of purchasing the module. A ridiculous, but true, example. There is a guy around the corner from my house. He has a Ford F-150. He had it painted Cadillac White and removed all of the Ford emblems and replaced with Cadillac emblems. Hey, he did not like the Ford branding so he replaced with a branding that he did like. Another option is to just remove the branding and leave it blank.