The past couple of months have been pretty clean from SPAM in the secviz feed, after I implemented a moderator queue for all the content. This seems to work pretty well. However, the system doesn't let me enable a moderator queue for images in the image gallery. That's why you have seen a few SPAM images in the feed (for example this morning).
I took another step to prevent this. When signing up as a user, you will have to be approved from now on. This seems to be the only way for me to prevent SPAM once and for all. I hope I'll be able to distinguish real users from spammers upon signup. I'll figure that one out.
Looking forward to seeing your posts here!