I think the "mangling" refers to something you can see in this
example from the AmAstro mailing list:
http://groups.yahoo.com/group/amastro/message/10522
The address has been rendered as "healydave@s...".
Click on it, and you can reply _if_ you're logged in to
Yahoo and go through their reply mechanism. The recipient
can see your un-spoofed e-mail address, and it's probably
tough for most spammers to get around this (and easier
to rely on spambots.)
Addresses within a message are similarly mangled.
Take a look at the Guide user list, and by contrast,
you'll see that e-mail addresses are sent "in the clear",
accessible to passing spambots.
Seems like a nice feature, but given that we lose the
very helpful ability to ban spammers and can't reverse the
procedure, I'm leaning against implementing it.
-- Bill