When is crowdsourcing appropriate? What makes a good project for this method?

When is crowdsourcing appropriate? What makes a good project for this method?.

 Description Please read: 1.http://dlib.org/dlib/march10/holley/03holley.html Crowdsourcing: How and Why Should Libraries Do It? Rose Holley 2.http://www.dlib.org/dlib/may17/vanhyning/05vanhyning.html Transforming Libraries and Archives through Crowdsourcing Victoria Van Hyning, Samantha Blickhan, Laura Trouille, Chris Lintott 3. https://www.scribd.com/document/51606855/Crowd-Sourcing-Systems-on-the-World-Wide-Web-April-2011-Communications-of-the-ACM Crowdsourcing Systems on the World-Wide Web: The practice of crowdsourcing is transforming the Web and giving rise to a new field. Anhai Doan, Raghu Ramakrishnan, Alon Y. Halevy Then please write about 2 pages on: When is crowdsourcing appropriate? What makes a good project for this method?

When is crowdsourcing appropriate? What makes a good project for this method?