Radius is being relaunched as a platform for communities, groups, events, and activities. Creator Sarah K. initially planned to show all event types but narrowed the focus to help people connect through shared interests. The original Show HN received over 150 comments with extensive feedback.

The relaunch adds "Activities" — lightweight events independent of groups where people post what they are doing with a time and place, and others can join or vote on times. Examples include cycling or coffee meetups in cities like New York and Edinburgh. Radius is built with Ruby on Rails.

The platform offers hyper-local discovery, browsing of groups worldwide, and free community creation.