ArcNote is an app that's difficult to describe in a few, short words. So, let me have some visuals do the talking. Look at the screenshots below, and you'll probably pretty quickly understand what this app does.
Now that you've looked at them, you probably realize this is kind-of-sort-of amazing. If you're constantly in meetings, or attend some kind of higher education institution, you probably see a lot of PowerPoint / Keynote slides.