I see you allow file uploads. How do you handle file storage, isn't that potentially expensive (DOSing your bank account)? And what about legal problems (copyright infringement and illegal stuff)?
I don't have much disk space available so if the limit is exceeded I will delete files that have not been downloaded recently. Active files stay longer.
Legal problems I have not put much thought into, but anything reported or found by me will be deleted immediately. Client side encryption and decryption could come in the future.