...and 16-line (1300+ character) monstrosities as seen here:
http://en.wikipedia.org/wiki/Wikipedia_talk:Sign_your_posts_on_talk_pages#Nice_Signatures

I'd like to see a 200 character limit (or even better, a 150 character limit).
The most colorful sig I can think of (that noone (except me) has complained
about) is 175 characters
(http://en.wikipedia.org/wiki/User_talk:The_Transhumanist#10_chars_shorter).

A (slightly controversial) alternative suggested in this thread
(http://en.wikipedia.org/wiki/Wikipedia:Village_pump_%28proposals%29#Reduce_the_size_limit_for_sigs.3F)
is to remove the custom signature ability altogether, but replace with the
option to add a 'talk' link after the username in the sig. E.g.
[[User:Username]] · [[User talk:Userame|talk]]

Nikolas wrote:

I'd go for 250 chars which would prevent most monstrus situations, while maintaining
the 'grey' ones for case-by-case evaluation.

ayg wrote:

Remember that it probably needs to be at least as long as the longest possible default
signature. That's about six characters plus twice the max username length plus twice the
length of the user namespace, I believe. Of course, de facto max username lengths might be
shorter than whatever the maximum technical limit we have is on some projects.

If someone has a 50 character username, they darn well better be piping it to
something shorter... (Hence even with a talkpage link, it'll end up <200 chars.)

ui2t5v002 wrote:

Also see [[Wikipedia:Village_pump_%28technical%29#Signature_length]], where we
suggested using templates for signatures (oh noes!1), while simultaneously
limiting the server damage they can cause.

If the only template allowed in signatures was {{User:Username/sig}}, the /sig
page could be made into a special page, like User:Username/monobook.css. At the
very least, it could provide a message on editing (like the "Tip: Use the 'Show
preview' button..." message on monobook.css) encouraging short sigs and saying
to not change them all the time.

Better yet, it could be made so that you can only edit that page once a month or
something like that, or the sig templates could get an extremely low priority in
the servers, so that changes to them only propagate during times of low server
load. So if someone changes their sig template every day, the changes will
slowly trickle out through the site only after a week or so.

This would solve the server load problem, the talk page code clutter problem,
and the "i need an oh so cool signature that changes every day to keep up with
my frequent username changes" problem at the same time.

robchur wrote:

(In reply to comment #6)

Better yet, it could be made so that you can only edit that page once a month or
something like that, or the sig templates could get an extremely low priority in
the servers, so that changes to them only propagate during times of low server
load. So if someone changes their sig template every day, the changes will
slowly trickle out through the site only after a week or so.

This would require adding a lot of special-case stuff for signatures, which is
not a path we want to travel at all. Complicated signatures are not important
for the primary goal of Wikipedia, and we certainly aren't about to change
MediaWiki to give them special treatment.

A length limit seems adequate to my mind.

ui2t5v002 wrote:

(In reply to comment #7)

This would require adding a lot of special-case stuff for signatures, which is
not a path we want to travel at all. Complicated signatures are not important
for the primary goal of Wikipedia, and we certainly aren't about to change
MediaWiki to give them special treatment.

It wouldn't *just* be for long stupid signatures. It would be for any
low-priority templates; when it would be nice to use a template, but the
template would hurt the servers if changes to it propagated immediately. (That
*is* the main reason why templates are bad for the servers, right? Because a
change to a widely-used template invalidates the caches of every page it is used
on?) But there are many templates like this where it's not important that the
changes propagate instantly, and the caches could be invalidated only during
periods of low load.

A length limit seems adequate to my mind.

:-\ Even length-limited sigs are hard to read around compared to
{{User:Username/sig}} (even with syntax highlighting). The people discussing
length limits on the Village Pump are suggesting things like "200 characters" or
"5 lines". Ick.

For the record, I'm not trying to claim that long stupid signatures are helpful.
I don't use them and I don't like them. But other people like them and are
going to use them, right up to the edge of the limits that are imposed on them.
I want to make this situation easier for others, such as myself, to deal with.

ayg wrote:

*** Bug 10177 has been marked as a duplicate of this bug. ***

See gallery at [[User:Athaenara/Gallery]]

matthew.britton wrote:

I think 255 characters is a reasonable limit. Anyone with a username long enough to make that a problem (it would have to be over 100 characters, for them not to be able to make the default [[User:Foo|Foo]] link to it) is likely to be blocked anyway.

Added $wgMaxSigChars in r22960, defaulting to 255.

This is partially broken. See T40974: $wgMaxSigChars can be circumvented by using templates.

(In reply to comment #13)

This is partially broken. See T40974: $wgMaxSigChars can be circumvented by using templates.

T12715: A user can get around the 255 character signature limit via template substitution it is.