And again, why?
Once more I see an app and I ask "What does this app do for me the related web site does not?"
For TED, I will append "or that the associated Web site + a bog standard podcatcher doesn't?" - I have GPodder set up to pull down the TED talks videos, so I don't have to be online to watch them - and my podcatcher works with other sources as well.
As (one of the various interchangeable cooking show people I cannot be bother to remember with specificity) says, "I hate single-taskers in my kitchen! If it cannot do more than one thing who needs it?" Why do I need to clutter my phone with a large number of single-purpose apps when a couple of general purpose apps will do as well or even better?