It seems I am not alone in this pet peeve.  I received enough email to do an "Email etiquette" diary.  I'll save that for later.

Here's the general consensus:

1.  4 lines
    <name>
    <Title>
    <company>
    <phone number or web address>
2.  Quote are okay as long as:
    a) It's kept to a minimum
    b) it's kept to PERSONAL email only
    c) It's does not have a racial or religious theme.  (duh?)
    d) plain text
3.  Plain text
4.  Plaxo and LinkedIn are bad.
5.  jpg's/gif's/png's are bad. (no HTML!)
6.  Apparently in some parts of the .eu, you HAVE to put stuff in your Sig block like, company name, web site, email, for disclaimer purposes. 
http://www.out-law.com/page-431
7.  CERTS are okay, but as one reader pointed out, "Why tell people what you don't have?"
8.  Addresses are to be kept out, if I want your address, I'll ask you for it.  Email addresses should also be kept out, since it's going to be in your Reply-To:
9.  The only thing worse than big long Sig blocks is OOOR.  (Out of Office Replies)
10.  Last but DEFINITELY not least.  The Disclaimers that say stuff like:

"IF YOU ARE NOT THE INTENDED RECIPIENT OF THIS MESSAGE YOU MUST DELETE AND NOTIFY THE SENDER BLAH BLAH BLAH BLAH BLAH, OR YOU CAN BE FINED 500 BUCKS BLAH BLAH BLAH, INSERT 20 MORE LINES OF STUFF HERE BLAH BLAH BLAH BLAH".   

Has anyone ever seen one of these enforced?  Do you have a link to case law?  I'd like to make fun of it.

Bottom line from the group?

Keep it short, plain text, and simple.  HTML, logos, quotes, disclaimers, etc..  are not necessary and do nothing but keep short email replies long.

Oh, and for those email clients that don't recognize that "--" is the start of the Sig block (Outlook, Lotus), please, fix your stuff.  (from a reader). 

Oh, and if you are replying to a reply..  trim your Sig.

Thank you all for writing in, hopefully I've influenced enough of you to take a look at your sig lines and trim them up.  They are getting out of control.

--

Joel Esler
http://handlers.sans.org/jesler