An extensive PS4 FAQ released today on the official PlayStation Blog declares that, contrary to earlier reports, PlayStation 4 will not support video streaming or uploading to YouTube via the DualShock 4's Share button.
This detail flies directly in the face of what Mark Cerny told Jimmy Fallon on a late show appearance a few months back, but it's worth noting that Ustream and Twitch streaming (along with Facebook and Twitter uploading) are supported. And, it's possible things could change down the line. FAQ author Sid Shuman notes, "PS4 owners can follow PlayStation.Blog and PlayStation.com for further news on other services to come after launch."
Livestream archiving is not supported via Ustream, but Twitch users can enable the feature in their Twitch account settings.