Twitter's live-streaming app hit a big milestone on Aug. 10th: the company now has 10 million accounts active on iOS and Android, founder Kayvon Beykpour said in a broadcast today. The company reached that number about four months after it launched; Periscope hit 1 million users in its first 10 days.

Beykpour said the more significant milestone for the company, and its preferred metric for judging the success of the app, is the amount of time watched each day. Users collectively watch 40 years worth of content daily on Periscope, he said. And that's just on iOS and Android — web streams aren't yet included in the count. "There's no better metric that illustrates that people like and are using Periscope."

Beykpour also fielded some feature requests during the broadcast. He said the team will consider adding a fast-forward button that would let users fast-forward through streams upon replay. He also said the company is working on new features to reduce spam and abuse on the platform, and on a feature to let users broadcast with their devices in landscape mode.