The "Share" button on PS4 promises to make uploading gameplay clips much easier than ever before--especially with Twitch and Ustream integration. However, don't expect to capture games in their entirety, as the ability to record gameplay comes with caveats. Notably, developers can restrict what footage can be captured in their games.
In an FAQ, Sony stated that users will not be able to record, distribute, or stream entire game playthroughs. "Users may not be able to record certain areas within the game," the FAQ states. "Developers can select the area of restriction, and what will be restricted will depend on game titles. In these cases, recording will be temporarily suspended during the scene."
In addition, PS4 cannot share videos to YouTube at launch. Savvy users, however, will be able to get around this restriction by using the YouTube function from their Twitch video archive. Users will also be able to make use of an external HDMI-based capture device following a post-launch system update.