After scaling back operations and reassigning staff to other projects, Tumblr owner Automattic’s CEO Matt Mullenweg said that the company would home in on the parts of Tumblr’s service that worked and kill those that didn’t — as it did with the subscription offering, Post+ last month. Now the company wants to focus on the former by launching a new feature that capitalizes on something Tumblr already does well: help people find communities. Today, the Tumblr Labs division announced the launch of “Communities,” an experimental feature that offers a new, dedicated space on the platform for people to network around topics of interest, separate from the main dashboard.