Miss Fortune is a very good Carry with and without a Supporter on Bot Lane.
With her passive she is able to make fast backdoor and roaming jobs and if you play her well and good you will see that she is MUCH better then you ever saw her.

Why this Runes here the explanation.

Marks:
Damage: Why Damage? Because with +8,5 dmg the last hit much easier and farm better.

Attack Speed: If you are able to make Perfect last hits without any damage item you can choose them.


Seals:
Attack Speed: Faster Auto-Hits with her W-Skill she get 1.0 Attack Speed only with dorans ;)

Damage: If you take Attack-Speed Marks, i prefer damage seals better then Only Attack Speed in earlier game.

Armor: If you wanna play more tanky choose them.


Glyphs:
Attack Speed: Like Seals

Damage: Like Seals

Magic Resist: Like Seals



Quintessence:
Life Steal: They are expensive, but very usefull with Dorans Blade you have 12% Life Steal with lvl 1, thats good when you play without healer

Armor Pen: You need to brake enemies Armor, but with your black cleaver you dont really need

Damage: For easier Last Hits

Attack Speed: For Faster Attacks

why 21/0/9

you need the 21 on Offense for things like, 3% Life Steal, 10% more crit damage, 4% Attack speed very usefull

the 9 on Utility, because you have 15 sec less flash cooldown, 30% longer buffs and more Movement speed

I like that masteries on nearly every Ad Carry.