That looks very good. How do you plan to manage spammers ?
What do you mean by spammers?
If you're talking about email, Webscript can be made to talk to an SMTP server, but whoever writes the script could presumably have talked directly to that SMTP server instead, and that would have been more efficient. So why would Webscript be used for spamming?
1. It doesn't require authentication. (If it required authentication, then there would be no way to gain anonymity.) I think this is extremely rare these days.
2. Other SMTP servers are willing to receive mail from it. This seems unlikely, since such a server is almost certainly going to be used to send a lot of spam.
3. This open relay keeps track of the sender in some weak way (since there's no authentication), like perhaps IP address. (If this weren't the case, there would be no reason to use a third-party service to hide your identity.)
If you could find some SMTP server that met all these requirements, then you would have motivation as a spammer to use a third-party service to hide your IP address. But a VPN would be a better way to do that then using something like Webscript. Webscript will be comparatively slow, we're likely to shut down a spammer because their traffic will be heavier than what we expect/allow, and we don't have a lot of IP addresses, so we would certainly just get blocked at some point just as the spammer would have if they hadn't been using us.