I run public servers for Glasgow for some of the decentralised projects I find interesting. Most of them use the ActivityPub protocol.

• https://glasgow.social - Mastodon, a Twitter-like platform for microblogging
• https://lemmy.glasgow.social - Lemmy, a Reddit-like platform of forums (subreddits/subcommunities)
• https://matrix.glasgow.social - Matrix, an IRC (Instant messenger) like platform for chat rooms etc (similar to Discord)
• https://pixelfed.glasgow.social - Pixelfed, an Instagram-like platform for photo sharing
• https://peertube.glasgow.social - Peertube, a Youtube-like platform for video sharing

I also run a Wiki for Glasgow. While it isn't decentralised, all the data is available as both a download and a Gemini site: gemini://wiki.glasgow.social

I'm collecting some links that sum it up better than I can:

• The Oatmeal: Reaching People on the Internet in 2021