MapBoard is a online map with whiteboard doodling tools and as many users as you want! It updates in real time, and is a great way to share and collaborate on ideas that have a location. Currently in alpha :)
8 Alternatives to Sketch
Discover your next favorite thing
Product Hunt surfaces the best new products, every day. It's a place for product-loving enthusiasts to share and geek out about the latest mobile apps, websites, hardware projects, and tech creations.