Q:

Displaying W3C compliance

I think most people agree that complying with W3C standards is a worthwhile pursuit.
However, do you advertise the fact that your site is compliant? Are there positives or negatives to doing so?
If you do display your compliance, how do you do it?

A:

I don't, because the average user has no knowledge of what it means for a website to "be valid".
If someone who cares about such things is interested, they probably wouldn't take my word for it anyway - they'd run my site through the validator themselves, probably using a tool such as Firebug.

A:

It depends on your audience. If it's a tech site, you may promote your compliance.
If it's a simple blog, it's just superficial.
There are buttons that link to the W3C, that immediately validate the referer site (as a check for your visitors, if you misplaced it).

I would put a little text with such a link in the imprint or about page. So interested people can look, but the normal user is not annoyed.
Such a button on every page would just steal space :)

A:

I don't, mainly for two reasons:

Nobody cares, and those that do will
probably be using a Firefox
extension that tells them anyway.
Being 100% valid isn't the be-all
and end-all in web design, there are
sometimes legitimate reasons to
break validation.

Obviously #2 requires great caution, when doing the initial CSS build having valid markup is a must, and any errors in the final build should be well justified.
I also used to think that as a web professional it went without saying that my markup was valid, and to a certain extent that's still true but as you can see my standpoint has moved some what.

