How do you keep what you learn at conferences?

I’m building Eventnote and launching it here on 3 November. Before that, I’d love to learn from you.

At conferences I used a paper notebook, my phone’s notes app, and lots of slide photos. A few weeks later I could not remember what a photo was about, or which talk an idea came from.

How do you do it?
• Notebook, notes app, photos, or nothing at all?
• Do you ever go back to your notes and photos after the event?
• What do you wish worked better?