Use Sky/Onedrive also some of google drive worksSky/one drive works perfectly, google drive's text document application works aswell but its powerpoint, and excel don't. The video player for google drive works flawlessly with the youtube player extension. So you have your document creating, and editing down with the WiiU. Google drive video player works exactly like youtubes and video files do play just fine like it. On the orignal wii you could use the photo channel and play some .mov formatted video files up to whole movies but this took a lot of effort to convert video formats around and hoping that the audio and video doesn't become distorted in the process. They took the photochannel off the WiiU's wii menu and shop.
Play HTML 5 gamesVery simplistic HTML5 games that only use arrow keys and touch/mouse click inputs can work for this. The gamepad's dpad works as arrow keys I believe, though I could be wrong and they might just be registering as a controllers dpad which HTML5 games can use. If you try to use a USB keyboard it will not work for some games, usb keyboards only work when the virtual keyboard comes up. So only a few games will work. I suggest sites like scirra arcade because it is construct 2's hosting site which many people actually make their games for touch screen devices aswell with simplistic controls. Keep in mind not every game does. The major problem with the WiiU's web browser is there is no java and there is no flash player support. With the Wii you had at least flash player 7, but even in the Wii's menu you can not get into that web browser which I personally liked a lot more. Most of the games I have tried though have had performance issues with the web browser as well with HTML5 games.
Watch Google play moviesThere are verious methods of watching TV shows and movies. Some of the obvious methods are netflix, hulu, and amazon instant play. But if you purchase movies through google play service it basically gives you access to watch locked out videos on youtube. So you can use the web browser or youtube channel to watch the videos if you sign in. For the channel it requires you to activate it through www.youtube.com/activate and type in a code displayed on your WiiU's gamepad.
Stream PC Games To WiiU/Watching twitchtv streaming
Using various web based streaming services like twitch you can stream it to your WiiU and play pc games with a wireless controller. Unforchently using a remote access web browser software hasn't been a clear cut experience to play the WiiU gamepad with your pc, but it is possibly only with a wireless controller. So yes twitch does work on WiiU's web browser
Upload Screenshots to ANY websiteThe ability to upload to miiverse is a nice feature, but anytime you try to upload anything from the WiiU it tells you need to be in a game, and it will try to upload a picture any time you are in a game. This being the screen shots. This makes it useful for people who post blogs to get what they want to show done easier without depending on a capture card.
Super Mario Bros. Virtual Console
Screenshot taken on WiiU 4/27/2014