As you are all aware, Facebook displays a permissions box whenever you are about to install a new app. It's just giving the app permission to post things on your wall. This can be anything from your high score in a game to those terrible spamming apps that tell me I should click a link to see something I won't believe (i.e. spam). Those permissions may have gotten a little too frequent now with the introduction of Open Graph and an entirely new set of permissions being required. That's a problem according to Facebook.
On the developers blog, Facebook details their plans to consolidate the two permission actions - publish_stream and publish_action. The company claims that both of these permissions essentially allow the same thing. So there's no point in keeping them separate if the user is giving the same permission twice, right?
Well, at least Facebook thinks so and they think it will make the lives of developers and users a little bit better. I can definitely see why it benefits the developer since they only have to deal with a single permission box now instead of two. They can consolidate all the permissions they request of the user into a single request now.
Of course, there is another reason behind this change that is only briefly mentioned in the blog post, but is worth pointing out. It seems that Facebook wants to encourage developers to switch to Open Graph. To this end, they recommend that all developers switch to publish_actions.
There is still a use for the publish_stream option though. Developers will need to use this request when wanting to publish to somebody's friend's Timeline or to a group.
Another tip Facebook offers is to only request what your app needs up front and then ask for other permissions later on down the line. It seems that once a user accepts the first round of rather small permissions, they are willing to accept the larger permissions. This will raise conversion rates across the board or so they say.
As a final aside, it's worth pointing out that this change does not affect user controls. Developers still have to let users know exactly what it is they are asking to share on their behalf. So if you're planning on using this new consolidated request system, update your apps now.