Alas, they're like fleas. Go look at the QtWeb forums, where they seem to have given up scratching
I agree with siria, pre-inspection by a mod is needed, or rapid action when people report the threads.
OTOH, we assume it's real people making the posts -- what if it's only real people signing up? Maybe all we need is CAPTCHA for both phases, and some equivalent of a "hosts" file to block the IP?
Gigabyte H61M-USB3-B3 r2.0, I5-2400 3.10GHz, 4GB RAM; W7HPx64 SP1, Lotus SmartSuite 9.8, K-Meleon 76RC, Pale Moon 26.4.1, IE11, Clyton email 15.0, Foxit Reader 126.96.36.1996, PaintShop Pro 6.02, ZAM Free 2.74, SuRun 188.8.131.52, VoodooShield 3.59b
"Learning is not compulsory. Neither is survival." Dr. W. Edwards Deming.