Facebook's App Center is now live. If you live in the United States, you can access it right now. There are over 600 apps at launch and it's just going to get bigger from here on out. To help developers who are new to this to whole App Center thing, Facebook has a few tips.
It's important to remember that App Center is not like iTunes or Google Play. App discovery is the name of the game here so it's more important to present yourself well. Facebook has over 900 million users and they could all potentially see your app. Those users aren't going to care, however, if your app page looks like trash. Making a good first impression is going to leave people liking you.
Those likes are the most important thing to App Center. It's even more important than the ratings in other app stores. Facebook has made it painfully clear that an app has to be made of pure quality for it to even have a chance of showing up on the front page. Of course, it's all left up to the user and they're a fickle bunch. Impress them and you're going to go far, kid.
The other great thing about App Center is that pretty much anybody can use it. If you have a Timeline, Web or mobile app, it should be on App Center. Your app page will contain links to to your app driving traffic to you while giving back traffic to Facebook as only apps that use Open Graph are allowed on the service.
It's probably more important to use App Center if you have a mobile app. Sure, a lot of people browse the app stores on their respective mobile devices, but they use Facebook even more. Whether they're on the Web or on their phone, App Center will deliver content to their mobile device in no time at all.
Before the launch of App Center, app creators had to create an app page and submit it to Facebook for approval. Now that App Center has launched, that's not required anymore. Don't think it lets you off the hook though. Facebook will be constantly browsing apps listed and unlisted apps to make sure they have the most up-to-date information. If your app does not meet the quality guideline, it will be delisted from App Center. If it does and you're not on App Center, Facebook will automatically add it.
As you can see, growth on App Center is pretty much tied to one thing - quality. Facebook only wants the best apps to appear on App Center and it makes perfect sense. You can find all sorts of trash and throwaway apps on iTunes or Google Play. Facebook wants to be the gated community of app discovery sites and the apps must reflect that.
If you want to get on App Center, check out the documentation. It will show you how to clean up your app page and make yourself more aesthetically pleasing to users.