The live stream of NASA's Curiosity rover landing garnered more interest than primetime Sunday television, Ustream says. A spokesperson told Mashable that 3.2 million people in total had checked the stream at some point during the landing, with a peak of 500,000 people watching at the same time. That's higher than the estimated viewing numbers for CNN during Sunday primetime, which came in at 426,000, or MSNBC, which had an audience of 365,000 viewers over age two. Ustream's peak audience was lower only than that of Fox, which had an audience of 803,000.

"More people tuned in to watch the NASA Mars landing coverage on Ustream than many of the top cable news networks during Sunday primetime," says Ustream's Tony Riggins. Obviously, there are problems with this metric: for one thing, the Curiosity landing was a highly anticipated event, not really comparable to average weekend primetime viewing. Still, it's a sign that online video is becoming more accepted, as well as a further testament to Curiosity's popularity.