An example of crowdsourcing is Pinterest.  Pinterest is a pin-board in which people can put theme-based pictures, logos, and other pictures about hobbies, interests, events, and more.  Then, people can take pictures from other peoples' boards and create their own pin-board to share their board.  Also, if people think they can add to someones pin-board they can if it fits and makes sense depending on the ideas,hobbies, and interests on the person's pin-board.  Therefore people can get new ideas, recipes for food, and create new inventions from the ideas you get. This is a good example of crowdsourcing.
http://en.wikipedia.org/wiki/Pinterest
http://thedailydigi.com/pinterest-101-a-tutorial