Citizen science has gained popularity as a means of engaging public participation in the scientific endeavor. Large-scale citizen science research began with bird monitoring in Finland in the mid-18th century and the Transits of Venus Project in Victorian England, but the Internet has literally transformed our capacity to harness the small acts of many to tackle large problems of collecting and processing data. The geographic coverage and quantity of environmental data generated is unprecedented, creating a need for innovation in informatics, cyberinfrastructure, web application development, human computation, and data mining. Recently, citizen science has come under the influence of smart phones and social networking with profound social and scientific consequences. The speakers represent prominent recent efforts in citizen science, highlighting its expansion into new realms. The Internet and computer science have made possible the social and scientific interactions required to harness people's ingenuity, skill, love of nature, altruism, and playfulness into problem solving, invention, and completion of complex tasks. Not only are biologists crossing boundaries and working with computer scientists, the line between professional and public participation in science is beginning to blur, stirring tremendous excitement in the field of informal science education. This symposium features new tools and perspectives on this exciting endeavor.