You may have noticed iTunes Match, whatever that is*, has shown up in iTunes as part of some new Apple marketing initiative of something. The question may then become, "since I am not interested in beaming all my music to Apple for $25, how can I make this ad go away?"
The answer is to click it, like you really do want to pay Apple $25/year to transfer your music to Apple**. Once it dials up the mothership you get the option to click, "no thanks, my life is already inundated with advertising on everything I own and touch, and no I'd rather not just give in to inertia and fling more money at you," at which point the whole thing folds up and disappears. iTunes Match will vanish from the iTunes sidebar.
This isn't an ideal solution, but since the universe itself would collapse in to a quantum singularity of infinite mass and density if you weren't drowning in advertising, it is clear that simply putting an option in Preferences to disable it was off totally off the table.
* Yes, I know what it is, but it's the principle that's at stake here!
** Where it absolutely positively will never ever possibly be handed over to the record companies to troll for people to sue for copyright infringement.