@mhoye Given how little collaboration there actually tends to be within projects, I'm not sure how huge of a loss this would actually be...
That said, I've heard proof-of-work tends to be an effective means of raising costs on spammers without inconveniencing others, here's an NLnet-funded project: https://mcaptcha.org/
076萌SNS is a social network, courtesy of 076. It runs on GNU social, version 2.0.2-beta0, available under the GNU Affero General Public License.
All 076萌SNS content and data are available under the Creative Commons Attribution 3.0 license.