Tumblr made some changes today.
One of them is Public Groups. You can now start multiple public tumblelogs, and you can give access to other users. For example, you can now use Tumblr to host a blog for your band, giving everyone in the band the ability to post. And Tumblr can host it at yourband.com.
This is a major step in Tumblr’s evolution as a publishing platform.
— Meta Tumblelog時代の到来か。
