I've deleted the spam and the account. We get quite a lot of it, normally users with links in their signatures - but that's another topic.
I personally am against this suggestion for the reasons already posted: people will either post 5 crap posts or just post the ad elsewhere. And in any case, so long as it's bike / Fazer related it may actually be useful.
We will continue to delete the non-bike ads like the stuff we had today.