EugenRails is an amazing framework that has allowed Mastodon development to thrive and implement lots of, among other things, anti-abuse features.
Jonkman Microblog is a social network, courtesy of SOBAC Microcomputer Services. It runs on GNU social, version 1.2.0-beta5, available under the GNU Affero General Public License.
All Jonkman Microblog content and data are available under the Creative Commons Attribution 3.0 license.