We saw this behavior raising up especially around gifting like "put together some crazy photo for the birthday of a common friend" or "having all the photos of a wedding from the different points of view of the guests" or "collecting the photos from a company party or an event".
Main problem in doing this was that still a lot of users are not sharing all their photos on Facebook or they simply prefer to share them somewhere else.
That's why we started working to extend this feature to allow people to simply put photos together independently from where those photos are posted/shared/saved. Then up-sell premium services like, for instance, printing.
We were not ready to launch, but I put together a landing page on unbounce (http://hello.pastbook.com/shared-albums-for-everybody/) to receive feedbacks and beta users, just posted on hackernews few minutes ago (https://news.ycombinator.com/item?id=6283051).
It's built from developers with developer in mind: we'll allow every other photo-app to use our API to push/get content from these shared albums and provide books (PDF/PRINTED) on demand, as potential revenue stream for a lot of startups in the photography business looking for monetization channels.
Second would be to focus on other social networks rather than Facebook, probably Social Networks in Asia and other parts in the world.
If you can include some sort of messaging functionality (like whatsapp) that would be good. The integration of photos and messages would need to be elegant though.
Mobile is facebook's Achilles heel.
It's a really hard space to break into. The odds are against you.