Both TED and Ignite are not primarily an app and/or a video podcast. However I will focus on this aspect, as I have never been to an actual (on site) event of neither.
Both TED and Ignite make presentations about technology, science and culture available online for free. The vast majority of the presentations are interesting and entertaining. Some are even enlightening or inspiring.
While I had expected a presentation given by Veronica Belmont on memes to be fun, I had no idea a presentation on ‘The secret history of fonts‘ could be.
Ignite is a very narrow format (5 minutes with 20 slides that auto advance ever 15 minutes) and topics tend to be rather focused on things geeks will find interesting. The Ignite events are organised locally by volunteers. Some are filmed and made available online, some not.
The Ignite motto: “Enlighten us, but make it quick.”
TED is less strict format wise. The events are organised by a non-profit foundation and you will find some A-list celebrities as speakers. In general the tone and themes are more serious then Ignite. There is also a grassroots program of locally organised events called TEDx with a separate YouTube channel – however I haven’t looked into this.