In my humble opinion, if there is a way in which spammers could be stopped more easily and the pros of this forum are not lost, a change would be good. It is really annoying finding out that a reply to a question of interest is some "buy this shit" post.
I don't know how akismet works. I like the way stackoverflow dot com works, but I don't know if its FLOSS or not, hope it is.
Well, that's all I can propose by now.
Debian Stretch on Lenovo T450i, Lexicon Omega.
Pd-vanilla 0.49.0-3~bpo9+1 (installed from repo)