Destiny's beta phase was what you might call successful, according to a Bungie press release. The company says that 4,638,937 players participated in the testing period that began on July 17th.
"Hosting a beta at this scale is an incredible feat, so we're thrilled to see the phenomenal response. But the beta is just a taste of what's to come," said Activision Publishing CEO Eric Hirshberg. "This is the biggest beta of this console generation by a wide margin and the largest console beta ever for a new video game IP to date."
[Source: Bungie press release]