I think they repost things for a while at first because most forums won't allow you to post links to external sites until you've made
n amount of posts and been a member for
x amount of days.
Many thanks to all users that are contributed to this thread. I'm reviewed all and deleted the post and all the users implicated in this. Thanks a lot of! Its a great job!
I suggest adding a "Report this post as spam" to the forum, only for logged users; it would be more immediate than copying a spam link and pasting it in this thread. I've seen this feature in many forums around the web, and it works.
Also as I and others have said before, if you could also add the number of posts made by the user (either beside or under their User ID) it would further help.
I agree with both posts above.
Most other forums have atleast some way to deal with spam, and these Bots do not look like targeted spam... just "opportunistic" one. In the internet, there is a huge gap between being unprotected and even only slightly protected.
There are free measures against Bots in the internet, here's just one i found: https://captcha.com/. That would help so incredibly much.