The trouble with the 'real human' test is that it would kill email newsletters - how would you fancy manually verifying every DC newsletter that is posted ?
I used to use Choicemail One
, which required people that sent you mail to 'register' with you and wait to be approved. (you can also turn that feature off and still get fantastic spam blocking)
It also allowed you to manually approve addresses & domains and keep them out of the filter.
It did work quite well and none of my mailing lists I am subscribed to ever got an email asking them to register and none of my newsletters or lists were ever trapped by it, not even ones where the mail can come from many unknown senders, such as Topica lists.
The only problem I ever really had with it was the fact that mail I sent out to others was proxied through Choicemail One's Izzymail servers and ended up being caught in other people's spam filters, even though I was approved by the recipients already.
The only reason I ever used Choicemail One in the first place wasn't for spam reduction. It was the only known way, at the time, to get and send email outside of the proprietary software required by my ISP. It also transforms some webmail like Yahoo and Hotmail into pop3 without the need of paying for a pop3 account. They have since changed the rules at my ISP and I have ditched the software since it's no longer needed to do what I want.
I have since found out that there is a Choicemail Free
. It has less features than Choicemail One and can only be used with a single email account, but that might be all someone really needs and of course the price is nice (free).
Some people can get around the single email address restriction by forwarding all mail from one account to another, like Gmail users can. Then you just download it all from the one account and therefore only be using one email address with it. But all mail you send out will come from the one address you download the mail from and not your others. Might not be the best idea but if you have accounts that you recieve only with and not send mail, it's a thought to consider.