all possible and might work
Infinite storage is impossible
However there will be limited bandwidth, and limited time.
Like an unlimited mobile phone contract, you cannot talk for more than (60*24*31=) 44640 mins a month, and most people (they hope) talk for about 150-600.
Unlike voice, you can throttle bandwidth for heavy users (as isps do) - or ask heavy users to pay more for more bandwidth - but the storage is still free :)
Deduplication I leave to others, but would wonder how many of us encrypt our MP3/4 collections.
Of ~60GB of files, I have 30GB mp3, 20GB mp4/avi, 8GB photos and 2gb other
So, 1/6th cannot be deduped.
Getting clever, you could look at my music collection and make good geusses on things I would like if there was enough of a user base. Privacy is a subject for historians to invade