Facebook ethical issues of data collection

Question

If I have a Facebook application and my users agree to allow my application to access their information, photos, friends, etc., is it ethical to capture their information when they log in and then store it in memory, The next time it goes to my application, can it load faster?

If so, what about when the user logged out? Is it right to delete all cached information and photos that the user has provided?

Does Facebook have any way to detect that we are doing this (by storing their information, etc.)?

EIDT: just to be clear, the term and agreement of Facebook are not very clear on this issue (consent to access information is not always equal to consent to the preservation of information). Like where I will store the data, it will only be on the user drive, not on my own server. Therefore, I can not guarantee that the data will be encrypted safely (if someone steals the phone, that someone is likely to be able to receive the data)

And yes, my intention is to provide my users with a better application, not something else.

EDIT2: I am torn, one answer with very high voices says that this is normal because I provide the best user experience, but others say that I violate privacy. Can someone provide links to documentation? Or can more people vote? I am very happy for the answers!

Answer 1

You are not evil. Providing the user with a faster experience is beneficial for both the user and you.

With that said, if the data is not stored on your server in a secure manner, and you are unresponsive or careless with the security of this data, then this may raise some ethical issues.

Answer 2

I would say that it would probably be better if it were disabled by default, but it might suggest users to opt out of faster loading times. I think that many people will have a problem storing your personal data on your server for some time when they exit the application.

Answer 3

My answer is similar to @Keysmack. I believe that you should set the default value to "off" to cache the user's fb personal data. Denial of faster loading, performance, additional features, etc. - all these are good reasons.

The reason you should offer a default is because it is actually illegal to store user information without obtaining permission in countries such as Australia.

so make sure that you consider the legal requirements of the countries in which your users work, as well as FB T & C.

Update. Apparently, my country has adopted a new law that requires a legal requirement to store data for up to 90 days.