> solves this problem beautifully with a nifty feature allowing me to create a new proxy (“masked”) email address for every website but have the mail show up in my mail address ... So when the email gets sold and I start getting spammed, I can easy kill it, and also know who the culprit was

I do something like that too, but I have my own SMTP server. It doesn't use + it is just an entirely different email address for each one.

I can also easily send from any address by the -r switch.