It will all make sense if you follow this link (sorry PC or Mac users! The link only works on consoles): you’ll see a new YouTube interface that allows you to watch videos in full-screen! The overall navigation is simpler and an enlarged text makes sure you won’t suffer of any Banjo Kazooie-like “disease”.
Of course, this can be considered a sort of bad news for Xbox 360 owners since their console lacks a proper web browser (but, hey! At least they have video steaming) and probably a pro for PS3 and Wii consoles: we all know that YouTube is a real treasure when it comes to free video clips. And now that treasure is open to even more users!
Now here is a video tutorial from the official PlayStation Blog on how to use the YouTube TV on PlayStation 3 consoles: