What's next in mobile? Find out at MobileBeat, VentureBeat's 7th annual event on the future of mobile, on July 8-9 in San Francisco. Register now and save $400! “It’s not just our mobile app any more. It is Tumblr.” — Tumblr’s Peter Vidani Today, Yahoo-owned Tumblr is rolling out the ability to customize your blog’s design across any device — including its native iOS and Android apps.