Quoting spiralofhope (spiralofhope@???):

> Incoming musing..
>
>
> I haven't investigated the solution for email, but I would assume that
> many email clients can filter out signatures.

Frequently asked question, frequently given answer.

The prevailing convention as to .signature format is in 'Son of RFC
1036', originating in, but not specific to, Usenet netnews. (I.e., it
is also a social convention for e-mail.) The preceding delimiter for a
.signature is a flush-left two hyhens plus a single space character, and
then immediate a hard return -- a problematic choice for several
reasons, but it's the convention we have.

By prevailing convention, the user is free to use the following four
lines of up to 80 characters each for personal expression.

It follows that readers who for whatever reason wish to suppress the
display of received .signature blocks can do so with a trivial filter
recipe. If they cannot figure out how to implement such a filter with
their current software, they are free to change to different software in
which they can do it.

It is consider, by prevailing convention, gauche and clueless to
complain about someone else's .signature that immediately follows a Son
of RFC 1036-compliant '-- 'delimiter and is not excessively huge, because
it's within the power of that person to suppress .signature display with
a filtering script or MUA-internal .sigs-on / .sigs-off configuration
toggle, if such is provided. (But see below about advertising
typically evading this control method.)

The Internet, being the Internet, is well supplied with vocal people who
for sundry reasons dislike or indignantly refuse to comply with this
social convention, and/or claim it is obsolete or inapplicable because
blah blah blah blah blah. It nonetheless exists and persists, like
other netiquette guidelines.

The 4-lines, 80-columns limit on .signature size is called the 'McQuary
Limit', by the way, after George McQuary, one of the leading lights of
newsgroup alt.fan.warlord, where ludicrously excessive ('warlordable')
.signatures were creatively mocked on Usenet, back in its glory days.
Some of us therefore still put 'McQ!' into our .signatures as a nod to
the McQuary Limit and as a reminder that good taste and self-restraint
(the basis of netiquette) is still a good idea.

As to (specifically) _advertising_ autoinserted by some (noxious)
software, I would be extremely surprised if it were ever inserted after a
standards-compliant delimiter, let alone inside a McQuary-compliant .sig
-- because the aim of advertising is to force everyone's attention,
hence it is routine for such advertising to completely disregard
netiquette. And one gathers that the firms are also too clueless.

Therefore, filtering such advertising on the mail-receiving end becomes
more of a one-off problem, and a reason why a user who spews it onto the
Internet will tend to be viewed with disapproval until he/she fixes the
gaffe being committed in his/her name. (In other words, 'I didn't do
that; Avast Antivirus did!' isn't an excuse.)


> However, when I went looking through my email client (Claws Mail [1]) I
> couldn't find anything obvious! Maybe I didn't look hard enough.

Although this is not my problem (see above), you might consider
filtering .signatures via your mail delivery agent (MDA), whatever
that is.

Of course, if you're using, say, the internal IMAP4 support of Claw
Mail, then you aren't using a separate MDA, and cannot leverage an MDA's
filtering functions.

-- 
Cheers,                        My pid is Inigo Montoya.  You kill -9    
Rick Moen                      my parent process.  Prepare to vi.
rick@???
McQ!  (4x80)