App Pick: Google Spaces
Leo Laporte's app cap on iOS Today 297 is Google Spaces for iPhone. This is like a social network that's just meant for you and a small group of people. First create a space for a topic or a certain group of people. Share that space with friends using the built-in iOS share sheets. Once you've got people in a Space, you can share content using Google Search, Photos, and YouTube. You can even have conversations with friends right next to that content as well.
This could be great for events where you'd want to have notes from it and a way to keep in touch. Classes in schools could use this as well. There may be even more use cases to be discovered as time goes on.