"and automatically blacklist all IP networks that participated in creating these spam accounts"
I quote Denise's comment in he previous post: "a massive number of the IPs that are in those abusive-IPs databases are VPN IPs and that would have a tremendous amount of splash damage, so we'll never be able to do it."
I suggest you read the comments to the previous post on it as this answers several suggestions you've made.
Re: Invitation tree
"and automatically blacklist all IP networks that participated in creating these spam accounts"
I quote Denise's comment in he previous post: "a massive number of the IPs that are in those abusive-IPs databases are VPN IPs and that would have a tremendous amount of splash damage, so we'll never be able to do it."
I suggest you read the comments to the previous post on it as this answers several suggestions you've made.