One of the features announced when iOS 5 was revealed during Apple's Worldwide Developers Conference back in June was deep Twitter integration. What this meant to the end user was that any developer could easily implement Twitter into their app, allowing tweets, links, and pictures to be sent with ease.
There may be instances where a user doesn't want a particular app to have access to their Twitter account. In previous beta builds there was no way to prevent this--there is now.
Once you are in Settings, scroll down and tap on the Twitter option.
In early beta builds, this was the extent of the Twitter settings screen. You were able to add an account, or update your contacts' information, and that was it. Now, if you scroll down, you are presented with the option to allow or disallow access to your Twitter account app by app. Go ahead, scroll down to the bottom of this screen.
Here you will see any app that has requested access to your Twitter account. To deny access to any app, simply toggle the switch next to the app name from On to Off. Once access is turned off, when that particular app tries to access your Twitter information you will be presented with a dialog like the one below.
Of course, you can always go back into the Twitter settings and turn access back on.
It's great to see these little additions to iOS 5 as it gets closer to public release this fall.