recently more and more apps appear that retrieve data from Facebook and store it in some form for further processing purposes.
I have also idea for an application / service that would use Facebook API in similar way but during analysis phase I came across Facebook platform API policy page (http://developers.facebook.com/policy/) which says:
You must not store or cache any data you receive from us for more than 24 hours unless doing so is permitted by the offline exception, or that data is explicitly designated as Storable Data.
Of course - I've no idea how in reality 2 products above work internally, perhaps they refresh data they receive from Facebook every 24 hours but I do have some doubts about it. I expect that from purely engineering point of view, refreshing data for potentially hundreds of thousands or even millions of accounts is too complex process that would require significant amount of processing power.
I'm stuck at the moment because I've an idea which I believe is good one, but I don't want to invest my time in something that is not 100% crystal clear and legal.
Another thing is that relying on any such free API is in general very risky since terms and conditions may change over night.
Do you have any thoughts on this? Is there any legal way around this policy?