From the main page, I hovered over a link to a recently updated messageboard thread, and had the first few words pop up as a preview. It said "Blah blah blah Spoiler: important stuff players shouldn't know."
Going into the message, I could see that the spoiler tag worked properly, it just previewed weird.
Specifically, here's the thread:
http://paizo.com/paizo/messageboards/paizoPublishing/pathfinder/pathfinderR PG/ultimateMagicPlaytest/round1/changeWordingForMultiArmedCharacters
It just caught my eye since the spoiler stuff was exposed. No big deal, just thought someone should know.
It shouldn't do that! Gonna fix.