Can someone explain this to me?
 

http://www.pedalmafia.com/bike_ups_img/117_1.jpg%5Chttp://www.pedalmafia.com/bike_ups_img/117_1.html

That bike has vertical dropouts..I thought horizontal were needed for chain tension?

Explain what?

That pizza has green peppers. I thought black olives were needed for optimum deliciousness?

How that bike is a fixie w/ vertical dropouts

Do these pants match this shirt?

(Which bike?)

Link should be working..did the guy just adjust the chain length to be perfect?

yes, but they make your butt look big.

Those jeans don't make your ass look big, your fat ass makes your ass look big.

(Serious answer, he found the magic gear for that frame. And when the chain stretches, he'll just have to buy a new chain.)

ether perfect match on the gear OOORRRR its an eccentric bottom bracket shell.

like this:
http://www.philwood.com/Eccent4.jpg

with this
http://sheldonbrown.com/harris/white-hubs.html

or using a "magic ratio"
meaning that a few cog/chainring combos can work on any given bike with vertical dropouts, but when the chain stretches at all you're ****ed and need to run a tensioner

yes, but they make your butt look big.

Judging by the allen bolts, I'm gonna say it's an ENO hub.

We have a winner. The hub is also off-axis as you can see.

that bike looks cool, maybe i have bad taste. lol , i wanna build a bike like that

Plus, it looks like he's running a half-link, right at the seat tube in the image.

I may be wrong on this one but isnt a half link standard kit if your runing a magic gear unless you want putting on you wheel a total pain in the @$$

I think you're thinking of a 'master link' or 'quick link'. A half link isn't magic ... it just makes your chain a little longer. Some magic ratios need them, some don't.

And that is definitely an Eno. Off-center wheel and the allen bolts are good giveaways.