Potrero Hill has two parts. The northern part is a very nice high-end residential neighborhood. There's a strip of restaurants and local businesses on 18th Street: Goat Hill Pizza (sourdough crust), Umi (sushi), Farley's (coffeehouse), The Voice studio (singing lessons), Christopher's Books. If the local Whole Foods is too corporate for you, there are local groceries (The Good Life Grocery) and more businesses (like Pinkie's Nail Salon) up on 20th Street.
The southern part of Potrero Hill is the projects. O.J. Simpson grew up here. There's a mural with him on it on part of the projects; a few years ago someone spray painted the word "murderer" over his face. There's a footbridge over the freeway on 18th street. It had "gangsta crips" spray painted on it for six months. Someone drew a swastika on the lamppost and the next day the entire bridge was painted over, except the words "gangsta crips". If you're on Caltrain and arrive at the 22nd Street station, you can see a day spa at the bottom of a cliff and the projects at the top.
Immediately to the east of Potrero Hill is the old industrial neighborhood called the Dogpatch. It's also turning high-end.
"Potrero" means pasture in Spanish. There were two pastures here, the potrero viejo and potrero nuevo. Both were ejidos, or land for use by anyone, much like a commons. (Goat Hill Pizza got its name from this.) Because of that long-term common use the area was under disputed ownership until 1867.
Local bars include Parkside, Jacks, the Connecticut Yankee, Blooms, the Silhouette.
There's been a big to-do over the replacement of the Potrero Power Plant (though it's more over in the Dogpatch than on the hill.)
The Potrero Hill projects were in such bad condition that the Feds told San Francisco to shape up or they would step in and take over. A redevelopment plan is in the works. There's a bunch of controversy over the developer and who benefits and how much of it is affordable housing and how much is not.