When you're setting up your first Facebook app, there's a bunch of docs to read, you need to create keys/IDs, figure out the URLs you need to populate, understand how FB Connect works, etc. As someone who tinkers with FB apps and not actually launched one, it took me most of a day to setup a fresh EC2 instance and get everything configured. However, it took me only 10 minutes to get my first "Hello world" app launched, without having ever used Heroku before. That's the big step forward here -- a turnkey skeleton app that eliminates the initial frustration.
For big app developers, this is of no value. It's for tinkerers like the rest of us to get to baseline faster, and is designed for us to get sold on Heroku and get our feet wet with FB app development.
Let's use photos as an example to demonstrate the power and size of Facebook. This infographic shows the scale of photos stored in the Library of Congress, Flickr, and Facebook: http://s3.amazonaws.com/fromus/blog_posts/largest_photo_libr...
I work at New Relic, so I see a lot of companies (startups and otherwise) that have apps deployed on Facebook. The traffic they get is _insane_ and I don't see any indication that it's slowing down.
Games are an obvious category where Facebook dominates, but they are quickly becoming an obvious destination for new apps to launch, given the access to their social graph and the viral nature of the apps in general.
This isn't about hosting. This is about creating a living Facebook app in 5 seconds.
I think this is a big deal because the law of demand is a big deal. What the Facebook/Heroku partnership means is that if I'm some 19 year old with a cool idea, I don't need money or experience in hosting, I just have to write the code to do it. Calling that "modernising" is missing the point entirely.
To return to the iOS analogy, there were a lot of people who said "well, yeah, so Apple made an integrated platform for developing and selling software - but what does that get us that we didn't have before?" The answer to that question depends on whether you consider $1.7 billion in revenue novel or not.
If you create a facebook app using heroku, it looks like you get something akin to a facebook-boilerplate app that is already deployed.
I would imagine the people at Heroku / Facebook spending some effort in keeping their boilerplate app / demo up to date with any api changes that may occur.
If Facebook wants to get more developers to embrace their dying platform (when was the last time you heard about an exciting new FB app?), they'll need to silence the voices screaming from every corner of the Internet about their lame documentation and support.
Buy as usual, instead they do a song and dance announcing a new initiative and then completely forget about it, like their Stack Overflow support system which does not seem to have nearly enough participation from actual Facebook employees who can answer questions.
Even if you disagree with the above, you should agree that an API that accounts for 10% of a site's traffic, like Facebook's, is a struggling ecosystem. Src: http://www.businessinsider.com/facebook-news-feed-apps-2011-...