Comment 3 for bug 357864

This enhancement would be very helpful for me, for spam fighting. Here's the
scenario: Whenever asked for an e-mail, I invent one on-the-fly (e.g.,
"<email address hidden>"). This is a valid e-mail because I've set
up <email address hidden> to reach me. Later I can easily discover who betray my
e-mail to spammers (and prove it), and I can easily filter by that address,
which is very useful in case it reaches many spammers.

With Netscape 4.x, I have to change my Preferences to do this. With Mozilla 6.x
this is even more cumbersome due to the more complex Account Settings dialog.
Since we're talking about a huge number of addresses generated on the fly,
opening a new account for each is not a viable solution.

I'm aware of several people using similar techniques.

Perhaps the easiest way to add this to the UI is to allow adding a "From" header
using the same widgetry that lets you add other headers ("Bcc", "Reply-to",
etc.). Such a "From" header, if present, overrides the e-mail specified in the
account. This is very consistent with the representation of these headers in
e-mail transport, and it hides the extra functionality in a very unobtrusive
manner. Should, however, do something sensible in case several "From" headers
are entered (error dialog?).