Unless it is a common thread that is relevant to absolutely everyone, I can't stand seeing links in signatures. (To be fair here, I don't like outright links to other posts made by the poster)
To me it gives the impression of attention seeking, and it just clogs up the reading space with...links that I am extremely unlikely to click.
But I'm not much of a card idea person, so I'm probably a bit biased here. Probably not the happiest response you've ever gotten, but this has been brewing and stirring inside of me for a while...