Spammers can only work when making enormous amounts of connections each hour, so limiting a normal user to 10 connections per hour with some extra slack after two or three connectionless hours, with an hour blocking penalty if the user goes over shouldn't pose a problem to Joe Average and will definitely keep spammers at bay without the added administrative overhead of sending user's mail statistics. I think 10 is a bit low. I am not really an abnormal email user - but I tend to block answer a lot of emails, and send them as fast as I type them - so I can easily send 20-30 emails in the first hour, then maybe an hour slack, then another dozen or so - depending on inbound traffic and what arguments are ongoing on my mailing lists at the time. Ok, I could in theory use web forums, usenet (probably also subject to your rate limiting) or whatever for this, but tbh I don't think I can in
Erik Haagsman wrote: practice - if the discussion is on a mailing list, at best I would have to sign that list to a web mail account and reply that way, and as an average user I don't see why should I make life awkward for myself like that just to make life easier for admins (and I *am* an admin, so I have to look at both sides of the coin here) if you had (say) 30 emails per hour, accumulating unused emails until you have 200, then that might work - but again, I notice you are limiting by smtp session, and a spammer could easily send 100 emails each going to 100 recipients in a single session.