I find the E4ward service great, but I have one suggestion: add
support to the Yahoo! DomainKeys authentication system.

Apparently E4ward does nothing when forwarding a DomainKeys
authenticated message, while it still adds/changes some headers. Since
the original message was changed, the signature ends up broken, and my
real mail service detects the e-mail as having a bad signature, which,
I think, increases the probability of sending the message to the spam
folder (that's the impression I have, from a quick analysis of false
positives I noticed from the spam filter of my mail box).

A known solution is to resign every forwarded message. I think E4ward
should sign *all* forwarded messages -- even if the original message
is not signed --, since even if the real mail service starts to the
detect spam forwarded by E4ward as "good messages", for the user it's
just a matter of disabling the forwarding address.

DomainKeys, however, adds CPU cost to the server. Thus, I don't know
if signing all messages would be feasible for E4ward. Other solutions
are resigning only previously signed messages or preserving the whole
message after the DomainKey-Signature header.

(Details found on Wikipedia: <http://en.wikipedia.org/wiki/
DomainKeys>.)

Romulo A. Ceccon