Indeed. This would also allow us to reserve <code class=obscure> for some of our less-helpful answers or in-jokes. ;-)

You're right, Tank; "obscure" is a verb (tho I guess I was thinking of it as shorthand for "obscuration").

But "spoiler" is better... maybe the developers will incorporate it, as it's clear (in this context)and eminently remember-able!

I may be wrong here but isn't obscure also an adjective?
From google:
not clearly understood or expressed; "an obscure turn of phrase"; "an impulse to go off and fight certain obscure battles of his own spirit"-Anatole Broyard; "their descriptions of human behavior become vague, dull, and unclear"- P.A.Sorokin; "vague...forms of speech...have so long passed for mysteries of science"- John Locke
make less visible or unclear; "The stars are obscured by the clouds"
dark: marked by difficulty of style or expression; "much that was dark is now quite clear to me"; "those who do not appreciate Kafka's work say his style is obscure"
confuse: make unclear, indistinct, or blurred; "Her remarks confused the debate"; "Their words obnubilate their intentions"
hidden: difficult to find; "hidden valleys"; "a hidden cave"; "an obscure retreat"
make obscure or unclear; "The distinction was obscured"
not famous or acclaimed; "an obscure family"; "unsung heroes of the war"
make undecipherable or imperceptible by obscuring or concealing; "a hidden message"; "a veiled threat"
not drawing attention; "an unnoticeable cigarette burn on the carpet"; "an obscure flaw"
make difficult to perceive by sight; "The foliage of the huge tree obscures the view of the lake"
apart(p): remote and separate physically or socially; "existed over the centuries as a world apart"; "preserved because they inhabited a place apart"- W.H.Hudson; "tiny isolated villages remote from centers of civilization"; "an obscure village"

Oops...
I replied to the wrong node. This was meant for Re^4: black tags.

While that may be true, the usage in this thread was not quite in line with the adjective. It was meant more as a command.

Further, "obscure" under any definition is still a description of what is to be done (similar to "black") when a CSS tag could do any of these (black it out, blur it out) or anything else, too. Using a tag of "spoiler" is still a description of the text within the tags, allowing the CSS to do whatever the CSS wants and still make sense, which is what CSS was intended for.