"The fact that Google and Facebook were able to generate such enormous profits and growth does give hope to some companies," Mr. Ritter said. If start-ups can f

"The fact that Google and Facebook were able to generate such enormous profits and growth does give hope to some companies," Mr. Ritter said. If start-ups can figure out to convert a large user base into paying customers, he added, "it can be enormously profitable." Did Google or Facebook "convert a large user base into paying customers"? Is that what enabled them to "generate such enormous profits"?