The Second From Header
Mixmaster strips the originating address from your message at the first remailer. It's possible to add a second From header, right below the first where you may place a nickname, or possibly an email address. This second From will be passed on by some remailers, thus allowing you to maintain a persona from email to email, even though your message is anonymous. Some people make good use of this, particularly in newsgroup postings. Here's an example of two From headers:
From: QuickSilver <quicksilver@quicksilvermail.net$#62; From: QuickSilver
Here's another example:
From: QuickSilver <quicksilver@quicksilvermail.net$#62; From: John Jones <jjones@xmail.com>
In the first case I want only a nickname carried through. In the second, an entire email address. Of course, just inventing an email address such as I did here, doesn't make it functional. However, in both examples, there will be a continuity of sender persona with each message. Beware, though, anyone can use your nickname. Just because you choose it doesn't mean others can't choose it too. In fact, particularly in the case of USENET posts, others may try to fake anon articles from your nick. They may attempt to compromise your integrity and attribute any manner of thought, directly to you. If you use PGP to clear-sign your articles, no one can fake your signature. A simple check of the signature will indicate that bogus articles are just that. For more on clear-signing: Using PGP.
Unfortunately...
It's not so easy to use this capability as first appears. Only a few remailers provide it, so your chain must end with one that definately does. Also, some won't necessarily allow a full email address. Not only that, it's not all that easy to determine which remailers support nicks and which don't. There are a couple sources for this info. First, the newsgroup alt.privacy.anon-server.stats contains a report called Frelled From: Headers That sample was current at the time I write this (01/01/2010). You'll have to look at the info a bit to get the picture. It's only an example. Very likely, this included report is long out of data when you read it. Go to the stats newsgroup given and look for a current copy. Freshness is always paramount in remailer affairs. If it turns out that the report is no longer available, I recommend you go to the newsgroup alt.privacy.anon-server to seek the info.