9 overall if I'm not mistaken? Personally, I think there are not enough fences in Skyrim. Not everyone is that honest. Also, desperate times (war) call for desperate measures.

I always thought it was curious in ES games that people wouldn't by stolen items. It's like, how do they know which items are stolen?

Any merchant in Skyrim can become a fence. If anything, there are too many.

This. How do they know this random iron helm that looks like all the other iron helms is really someone's in solitude when I'm all the way in Falkreath?

Exactly.

Yep, I hated it when they implemented that into Oblivion, and I still hate it in Skyrim. I don't understand what was wrong with Morrowind's system of trading. 1st off, it was actually trading, you could get new items by giving your items, no gold needed from you or the trader, haggling was actually haggling, not a fixed price/cost scaling, and stolen items could be sold to anyone, but if you'd try to sell an item to a trader you stole it from he'd report you to guards.

It's a video game, not everything is meant to be, or is, realistic. For example; dragons.

There's also a perk that allows you to sell stolen items to any merchant.

Correct, but dragons are there.

There's no tag on stolen items that say "HEY LOOK I'M STOLEN DON'T BUY ME"

I think there's just the right amount. And if you think there are too few, just take the perk in the Speech tree and choose your own fences! Too many? Just ignore them.

perhaps they would ask your character where they had got it from and your character is not slick enough to make up a good story. They would deny buying something if it seemed shifty. They don't report you to the guards or anything, so it is not that they actually know, they just don't like the look of it and want to stay honest. When you get the fence perk in speech you can than convince them that it is not hot. This is how I look at it and it seems fine to me. I'm sure that these merchants don't buy something unless it looks legit and the character selling it doesn't look shady.