From what I see, a lot of the spammers will make a couple of posts overnight, hoping that a moderator will not delete it before someone can click on it.
By not clicking on the site, hopefully they will 'give up' and no longer post here.
Perhaps a rule where a new member must make 10 posts before having the rights to like to a external web site?
It does seem like it is the first or second post for a person that is a link that 'we' do not want on RV.Net
My guess is that RV.Net is more popular than the other websites that you visit. I know if I google search something that I might have just posted, it will come up on Google.com
Keep reporting, and not clicking on the links, and they will go away!
Good luck,
Fred.