When you open up the app you get a list of the recently posted videos to browse through. If you want to watch a random talk, you can tap on the 'Inspire Me' button and choose from videos tagged as courageous, funny, inspiring, informative, etc. that are a given length. I love this feature. You can also browse by themes or search for a specific talk by speaker or title. Overall, it's my favourite way to watch TED talks.
One feature I use particularly often is saving talks to watch offline. My iPad is WiFi only, so I'd rather have a selection available wherever I may be.
At one point, I had saved so many talks that I had over 4GB worth of video downloaded to my iPad. It became a problem when I had about 10 apps with updates and tapping the 'update all' button showed me an error message that I didn't have enough space to update.
To free up some space, I wanted to delete saved talks from my iPad that I had already watched. It should be a pretty straightforward thing to do, but it took me a while to figure out. This is where the "for the most part" comment above comes from. In hindsight it is fairly logical, but I spent way too much time swiping, tapping, and generally getting frustrated trying to find out how to delete them. And I've had so many friends ask me this question that I guess it's not as intuitive as it should be.
So how do you delete saved talks for the TED iPad app?
Just tap on 'My Talks' and hit the 'Edit' button in the upper left hand corner. The typical iOS 'X' will appear over each talk. Tap that and delete one at a time. The Edit button turns to 'Done' while in editing mode. Tap 'Done' to finish.