I wonder if there's a FF add-on that can strip query parameters by default on a cross-domain request?

Not exactly what you are asking for but https://addons.mozilla.org/en-US/firefox/addon/au-revoir-utm...

I edited the bookmarklet:

  javascript:window.location="http://news.ycombinator.com/submitlink?u="+encodeURIComponent((document.location+'').replace(/.utm_.*$/,''))+"&t="+encodeURIComponent(document.title)

Shouldn't you replace before URL-encoding?

It doesn't seem to matter. It's not as if "utm_" encodes to anything other than "utm_".

But encoded "?" is "%3F".

Hmmm, I have seen an extra '%3' occasionally... it never hurt anything so I didn't bother fixing it. Thanks dude now I'm going to be totally tormented until I fix my bookmarklet.

[EDIT:] ok moving that parenthesis and avoiding the update of document.location didn't take me too long...