When recent college graduate Bronson Chang wanted to renovate his uncle's candy shop in Honolulu, he decided to tap his social network for the funds via a "crowdfunding" website, instead of seeking a loan at a bank.

Crowdfunding sites—such as ProFounder.com, Peerbackers.com, Kickstarter.com and IndieGoGo.com—allow entrepreneurs to raise money collectively toward a monetary target. Entrepreneurs can create a profile on a crowdfunding site listing their monetary goals, an explanation of how the funds will be used, and an end-date...