I've seen others with builds that use acrobatics... How is it used? As far as I can tell you can jump on top of things?? But usually the enemy can still attack you. This is why I start the thread I am curious if its truly a dump skill or if it is any good.

It's like any skill- its usefulness isn't so much inherent, as in how you apply it. At the core it is indeed as simple as "you can jump higher and further." What you do with that decides how useful it is. Melee enemies can only still attack you if they can reach you, and not many can reach me when I've run to the top level of a fort ruin and leapt onto a standing column beyond their own jump distance. While that's useless to me if I'm also a melee character, it's easy street if I'm an archer or ranged mage type- I can fire on them at will, they can't touch me.

Also handy sometimes getting to things on remote ledges and such. And I'll admit while I won't train a character up solely for that purpose, there's a fun factor all its own in leaping from rooftop to rooftop through a town. (Which has also helped in the odd assassination mission- guards can't arrest you if they can't get to you.)

All in how you choose to use it, says I.

There are a few skills that are only useful in certain situations, and Acrobatics is among them.
I'd also say that Mercantile and Speechcraft are skills that aren't dire to anyone's build, unless you're roleplaying.

Acrobatics will improve on its own, because the game world is so frustratingly populated with rocks that you will end up jumping ontop of everything.
Speaking of rocks, most enemies can't climb, so jumping out of reach gives you a chance to swig a potion, cast a spell or ready another weapon.
It is best suited for people that use ranged weapony/magic.

In addition, acrobatics skill decreases damage taken from falls, but that's a bit broken. The factor by which it's decreased in the original game is so small as to be almost meaningless, however that's fixed in the Unofficial Oblivion Patch, so PC users can get that benefit.

Acrobatics also has some perks. At apprentice level (25) you can do regular attacks while in mid-air. At journeyman (50) you gain a dodge ability-- while holding block, you can jump in any direction and do a roll in that direction. However, that doesn't work when you're in melee range of an opponent, so it's not that useful as a dodge. It is a fairly quick way to stay out of range of a closing opponent though. You also gain the ability to do power attacks while in mid-air. At expert (75) your fatigue loss from jumping is halved. And at master (100) you gain the ability to jump from the surface of water. If you time it exactly right, you can actually jump multiple times and cross a body of water on the surface.

I like acrobatics for a major, since it's easy to control. If you jump or fall (far enough that you take damage), you gain acrobatics experience. If you don't, you don't.

Double -- sorry.

I cant think of a character I havent got high acrobatics in it so much fun to jump from ledge to ledge and make shortcuts of long dungeon paths.

Love finding an alyeid ruin with an out of reach varla or welknd or just another path above me, instead of going around the long way I jump. Also 50 Acrobatics unlocks the roll manuever which has saved my hide more than once.

As mumatil alluded to above, jumping can be handy. If you jump up on a boulder, the enemy cannot follow you.

The Acro above 50 benefit allows the dodge manuever. This can be used to unnock an arrow from your bow as well - very handy to save poisons and enchanted charges.

Right. It's clear from the formulas that Acrobatics is supposed to reduce fall damage.

Because of a simple programming mistake it doesn't to any meaningful extent.

Too bad. That would make it more useful. Also it was a known bug that is trivial to fix. But Bethesda has decided to leave it as a bug.