Ryan Lackey writes:

You need to make it easy to join the set (use standard protocols, no client software, and ideally make it require no user knowledge of the deeper darker purpose behind it all), and make it worthwhile to join the set (ideally a non-security non-messaging benefit, like "cool porn" or whatever)

What do you mean, "no client software"? How do you propose to get secure anonymous mail without client software?

2) 2-way communication is inherently much harder to secure, but is socially beneficial. Without socially beneficial uses, it's going to be a long and unpleasant battle, as it will be very hard to attract users. Regulation is NOT the reason PR matters; perception by users is.

A form of 2-way communication is possible already; this exchange is an example. Private (one to one) 2-way anonymous communication is harder, but in many cases it will be practical to use a group as a mediator. See the various PGP-encrypted posts on sci.crypt to Beale Screamer, who broke a Microsoft digital licensing scheme. Exitence of socially beneficial uses is good for political reasons and perhaps for getting people to run remailers, but has little impact on ease of attracting users. Users will be attracted for their own purposes, whether they are socially beneficial or not. Harrassment or anonymous love letters may not be socially beneficial but they are part of what people want to use remailers for. You seem to be implying that people won't want to use remailers for some good purpose just because they have a bad rep. Do many people really think that way?

3) "Sending anonymous mail" is *not* a compelling end-user application on a wide scale; nowhere near "have all the music you want available for free", "have arbitrary prohibited pornography" or "pay people anonymously".

No, but "communicating anonymously" is a *very* important addition to those other compelling applications you list. As the RIAA and governments crack down, people will want a way for people to trade music or porn without putting their IPs out on the net. Of course, email is not the appropriate transport for these applications. Maybe the conclusion should be that anonymous email should be seen as a special case of anonymous communications. Don't solve anonymous email, solve anonymous comm. A recent message on coderpunks proposed an alternative way to do anonymous mail: use pipenet as a transport for ordinary SMTP email. It was pointed out that timing information could link up the inward and outward connection in pipenet (a problem for any low-latency, transient connection). This could be addressed in part by maintaining several always-on, constant-traffic dummy channels into the pipenet.

4) Latency must be low. Anonymous (or at least private) online chat is more interesting to users than email. Feds own EFnet servers with regularity; people discuss plenty of interesting things on IRC, vs. most email. But, anonymous or even encrypted chat systems are a good deal more complex than mail. Also, low latency is good for messaging. Normal mail is "near realtime"; mixmaster is anything but. (most of the people who are likely to be users of anonymity are more comfortable with chat than email anyway.

In fact, many remailer users do preferentially choose low-latency remailers (partially because there tends to be a correlation between low latency and high reliability). And it makes online exchanges easier. Our various "Nomen Nescio" commentators are going through a remailer with only 5 minute latency. The problem is that low latency, low enough for chat, file exchange, web browsing etc. introduces many new technical challenges in terms of preserving anonymity. Still it is so much more useful that it would seem that working on solving those problems would be a better use of effort than doing anonymous email better. And as noted above, a remailing system might result for free.

(indeed, "develop e-cash to use as postage for remailers" is kind of putting the cart before the horse; "develop remailers to use to transport intermediate results of electronic cash operations" is the proper causality, I think)

Again, true with the proviso that it is not anonymous email you want, but a general form of anonymous connectivity.