Hi,
I took a look at the settings in the back end and there were a couple things that I could do right away. I noticed that the system was not set to scan the IPs of new users against the banned list, so I went ahead and enabled that. Please make sure that you One Touch Ban and Clean these spam posts when you do see them so that the IPs will continue to be added to the blacklist.
Akismet was something else that I noticed was not enabled. I have turned that on and set it to scan the first 5 posts of members for spam.
Now, if you feel that more needs to be added after this, there are a few steps we could take like adding the Cyb- Advanced Permissions Based on Post Count plugin to the site where we can restrict new members from posting links, videos, etc in certain or all sections until they have x# of approved posts. Another option would be to make a new usergroup promotion where new members posts are automatically added to the mod queue and will not be shown until approved by a mod. We can set it to promote them after they have x# of approved posts and/or have been registered for x# of days.
~Sheena