Yeah, I'm sure they're keeping A LOT of data. Metadata, search history, profiles browsing, app usage times and dates... Unfortunately there's no way to know exactly what data are they hiding, unless you're Zucks or something like that.

As far as I know, living in the EU does help: my understanding is that within the EU, all your data belongs to you even if it's stored by Facebook; as opposed as the US, where Facebook is the rightful owner of the data you provide.

Living in the EU does not help. In fact, this is the office responsible for overseeing data protection matters for all Silicon Valley companies operating across the entire EU:

https://www.google.nl/maps/place/Office+of+the+Data+Protecti...

And now you also know why Silicon Valley likes to have their European headquarters in Ireland. It's not just because the beer is fantastic.

I will try this for a bit more: http://www.europe-v-facebook.org/EN/Get_your_Data_/get_your_...

(but still no likes they say: (2nd paragraph) http://www.europe-v-facebook.org/EN/Data_Pool/data_pool.html )

Search history is indeed a nice example. It's so easy to prove (they autocomplete past searches, even if it's a long random string initially typed on another machine/browser)