Crowdsourcing involves outsourcing tasks to a large, undefined network of people or crowd through an open call over the Internet. It allows companies to harness the skills and insights of the crowd to help solve problems or complete tasks. Elance is an example of a crowdsourcing website that matches freelancers with employers seeking work. Employers post tasks and freelancers submit work, with the employer selecting the best solution. While it provides cost-effective solutions for employers and work for freelancers, there are also disadvantages like work not being selected or lack of long-term career opportunities.