Pointless: Something with no point
Pointless, Pathetic, Petrifying, Puke-inducing... :P
depends on who you are you see her songs pointless or not
Yes, it slows down your computer and it is pointless.
Pointless means useless or unnecessary.
A pointless fact is a fact that adds nothing to the argument.
Asking about pointless websites seems like a loaded question. That said, there are oddly enough, several websites devoted to listing pointless websites. These include The Useless Web, Pointless Sites and Pointless Web Pages, to name but a few.
The opposite of pointless (futile) could be effective, or valuable (important).
No maths has decimal points, so therefore no it's not pointless.