From not paying attention, I clicked on an obviously bogus Facebook link posted from a friend's hacked account. Should I worry, or did my using Linux probably protect me? Nothing unusual has happened since.

I would say you should be worried until you have reason not to be worried. Running GNU/Linux isn't IMHO a valid reason not to be worried. Sure, statistics are on your side on this one, but there's still a very real possibility that a GNU/Linux-compatible exploit was used. What browser (specific version) did you use? What plugins (specific versions) did you have enabled? Did you have NoScript (or similar) protection? What distro were you using? Was the distro completely up to date? The answers to these questions will help gauge the amount of risk you were exposing yourself to when you clicked the link. That said, analysing the actual page's content to determine what it was designed to exploit (if anything) would IMO be the most sure-fire way to determine whether you should be worried or not. Did you save the page (and its content files) for analysis? If so, could you send me a ZIP file of it (or alternatively, the URL to the actual page) via email?

Trying. Not sure I'll find it again...