Wesley Chan has a knack for turning good ideas into new businesses--and doing it with minimal resources. In 2005, Chan's small team at Google, which incorporated two startups he acquired for the company, launched Google Analytics to provide a free version of the tools the search giant previously used internally. In 2006, he dreamed up another free service, Google Voice, which launched in 2009. This one offers automatic transcription of voice mail, the ability to use one number for different phones, and many other features. Given only two company engineers to work with on the project, Chan acquired the startup ­GrandCentral in 2007; he and his new crew spent the next two years putting the service together in secret.

Google Voice now has millions of users. But Chan has moved on again and is now a partner at Google's venture capital investment group, Google Ventures. He still invests in software but is free to cast his net wider. In particular, he is developing an interest in stem-cell medicine, even though the field has no direct connection to Google's business. He says, "For me it's about going where I can learn the most, and making the output of my learning something that is world-changing." --Tom Simonite