I haven't ever been much interested in remailers, preferring overlay networks, but have been repeatedly implied to look into them by varied sources

mail and transmission instructions are encrypted to the remailer via normal email

the remailer decrypts, and sends on.

this can let one form onions.  including with cover traffic, I imagine

- I wonder how to find remailers

- I wonder what codebase is presently in wide use

- I wonder if there's a way to measure traffic

- I wonder if a remailer codebase is portable to public logging, to measure cover traffic and reveal a portion of any possible compromises