YouTube support has been considerably enhanced in iPhone OS 3. 1, now, when you exit a clip (tap Done), instead of returning to the list of clips you were at, you're presented two brand new tabs: A, an "Info" tab with the list of the comments and other info (tags, category, date, description). It also has a button "Rate, comment or flag". As you may have guessed, this allows for rating and commenting (too bad the latter doesn't work in landscape). B, a "More Videos" tab with the videos of the same uploader; this also allows for subscribing to the given uploader, assuming you're signed it. The subscription will appear immediately on your account. 2, I've already mentioned this in bullet B: you now can log into your YouTube account (under the "More" icon). After logging in, you gain access to not only the standard menu items (Most recent / Top rated), but also History, My Videos (a list of videos you've uploaded), Subscriptions and Playlists. With these enhancements, the only (not very annoying) difference between it and Windows Mobile-based Kinoma Play (which I consider to be currently the best and most featureful, albeit, video playback-wise, not the most efficient player on mobile platforms) is iPhone's YouTube not supporting changing the metadata (category, description etc.) of your own videos. This is, again, a minor disadvantage: Taking into account the worse video quality of Kinoma Play (QVGA resolution, as opposed to the higher HVGA on iPhone), I think I'll stick with the iPhone for the time being when it comes to YouTube playback now that, at last, I can browse both the comments of a video and the videos of the same uploader. The biggest problem with iPhone's implementation is that via 3G (UMTS / HSDPA) it seems to force the user to see the dumbed-down, low-quality (low resolution, mono - as opposed to the high-quality H.264 HVGA with stereo sound default delivered via Wi-Fi) video instead. There's no way of disabling this. This is a definite restriction compared to the Symbian S60 / Windows Mobile implementations, where 3G users aren't forced to put up with the low-quality stream. At least this is the case with T-Mobile, using a 3GB data plan, on a locked, non-jailbroken OS3 iPhone 3G. I assume this is the same with all the other carriers and even factory unlocked / jailbroken / yellowsn0w'ed phones.
iPhone already plays back HQ (320*480 H264) content. There wouldn't be much point in trying to play back e.g. 720p content.
Are you sure there would be any point in trying to render 720p h.264 on the iPhone 2G/3G hardware? I don't think even the 3G S could render it w/o skipped frames, let alone the much less multimedia-friendly 2g/3g....
