According to NeoGaf, there was a Youtube Upload feature for Smash Bros that was originally planned but was cut. User IntelliHeath discovered this while looking The Cutting Floor Room’s Super Smash Bros Wii U page:
Convert the replay data into a video and post it? This requires a Google account.
(Note: This process may take longer than the duration of the replay.)
Cancel the conversion process?
Download complete. To see it, go to Í and then Í.
Download and save?
Replays you’ve downloaded can be found in the Vault.
By connecting to Nintendo Network, you can send your replay to friends or show it off to the world.
Whom do you want to share this with? Data will be sent to the following number of people: .
Is this OK?
This sounds like a pretty cool feature to have. Of course, this has not been confirmed by Nintendo. However, if it is indeed true, maybe we’ll see it in a future update.