Sony notes that all retail PlayStation 4 games will need to be cached to the PlayStation 4’s hard drive, though gameplay can proceed during installation. Discs are still required for play afterward, and access will be limited to pre-installed data.
Players will need to carefully manage installs if they hope to maintain a large game library, however, as the console does not support external storage via USB hard drives or memory sticks. The PlayStation 4 also lacks DLNA support, eliminating client functionality for home PC media servers.
In addition, the platform does not feature a music visualizer, and ditches support for dynamic themes and .mp3 playback. Media will be offered via Sony’s Music Unlimited and Video Unlimited services, along with “other entertainment services that will be available on Day 1 before launch.”
Sony additionally addressed the console’s one-time activation requirement for DVD and Blu-ray playback, noting that players can request a Blu-ray activation disc in lieu of a downloadable update. The update can also be installed via USB.
Regarding the PlayStation 4’s Share button and video recording capabilities, Sony revealed that streaming, sharing, and screenshot functionality does not require a PlayStation Plus account. However, publishers may block specific gameplay segments from being shared, resulting in automatic suspension of recording during these sequences.
Source: Playstation Blog