Communication: Type 2 Remailers

Type 2 (or "Mixmaster") remailers try to fix the problems of type 1.

Break the messages into fixed-size chunks at the client, and send the chunks separately
This is better, but now you need special software at the client.
This is true in general: putting trusted software on your trusted PC allows you to do more secure things.
Nym servers also allow for replying to pseudonymous posts, using reply blocks.
No single remailer can link a pseudonym to a real email address.
But a concerted attack on many remailers probably could.