There was a slide that indicated that data from Apple and other companies was now part of the PRISM program.
I am not trying to deny or refute Snowden's whistleblowing. I think it is highly likely that PRISM exists. What I dispute are the speculations that the companies listed are complicit.
The 2012 date is quite suspicious - it is precisely the same year that a new Apple datacenter in Prineville came online. Facebook also has a datacenter. Literally next door. Facebook also appears on those slides. I am not sure who else is also now in the area.
I wonder where all of the network cables go?
I personally think that PRISM works by externally intercepting data communication lines running to these facilities. Similar to the rumors that international comms links have been tapped. The companies themselves have not participated, but the data path has been compromised.
The NSA has previously tapped lines (AT&T), but they made the mistake of doing it inside the AT&T building. Google "Room 641A at 611 Folsom Street, SF". That is where "beam splitting" was done. This eventually leaked out. The NSA isn't stupid, I doubt they wanted to repeat that sort of discovery. The best way to keep something from being discovered is to not let people know. This is why I think it is believable and likely that the companies listed on the slides have no idea what has been done.
I will also note that PRISM and "beam splitting" are a rather cosy coincidence.
I think it is most likely that PRISM is implemented without the knowledge of anyone except the NSA and in Prineville there is some "diversion" of network cabling to a private facility that is tapping the lines.