A a captcha for your first post or two.
I would like a captcha to have until someone become a member. Since users do not need any merit until s/he become a member, they are open to spam the forum.
I am not saying it's gonna stop the spamming 100% but this will at-least restrict the spammers. We could see some more merit abuse to achieve member rank though

That would be extremely annoying to anyone that uses public wifi, or any sort of VPN/TOR.
It's already an almost impossible task to do google captcha's on a tor browser, let alone if you have to do it multiple times for each post that you make.
but this will at-least restrict the spammers.
And anyone that values their privacy, which i think is a pretty large part of this community....