Open RiskTo me its all still quite confusing. Activitypub seems quite a bit less prescriptive, a lot of important details are "left to implementation". The Mastodon server network is one such fully developed architecture but quite different designs are compliant, e.g., single account "instances" like gotosocial. Somebody even suggested that the entire activitypub pattern could be implemented over the atproto protocol etc.
GNU social JP is a social network, courtesy of GNU social JP管理人. It runs on GNU social, version 2.0.2-dev, available under the GNU Affero General Public License.
All GNU social JP content and data are available under the Creative Commons Attribution 3.0 license.