I run a number of services mostly for myself (but some I open to friends or the public) as an alternative to relying on the surveillance capitalist walled gardens like Twitter, Facebook etc.
This is my public wiki, which is a collection of documentation I'm working on that supports either my own projects or acts as a knowledge base of personal information that I'm happy to make public.
I also run a private wiki which is my personal knowledge base of links and snippets I discover and just general notes on ideas and projects that aren't ready to publish. I've had something like this in one form or another for almost 20 years. Originally starting with WikiWikiWeb, dabbling with my own creation, switching to MediaWiki, my own custom experiments again, and currently on Dokuwiki. I'm very happy with Dokuwiki, but I'm often exploring more user friendly alternatives as I try to introduce more wiki use among work colleages and in public projects.
I run this to host personal files as well as share a calendar with family (it's accessed via WebCal on phones etc). I'm quite new to using it (2020) but I'm impressed with it's functionality and ease of use so far.
I've been keeping regular notes of what I get up to on a daily basis, as well as people I meet, movies I watch and books I read, among other things. This all get collated by a bit of custom software I've been refining for years. Within a few seconds I can check when I last saw someone or when I last visited a bar or restaurant, or get a reminder of the name of someones partner. I can also easily compare dates, for example, see what I did for the last ten Christmas days and so on. I access it with an API and get 'this time last year' reminders on Matrix.
I wrote a custom double entry book keeping system a long time ago, that I use to record every transaction I make. It gives me a great handle on my finances and has historical spending data starting around 2005. There are quite a few changes I'd like to make to it however - I'm considering re-investigating what's available in the open source arena again (I used Gnucash years ago but needed a web interface, so I built my own).
I run a Matrix-Synpase server to provide a more user friendly alternative to IRC. I'm quite enamoured with the Matrix protocol. Anyone is free to create an account, they can access the Elemental (Riot) web interface. The server is mostly friends of mine based in Glasgow but there are some people using it for other things (for example; the Scots Wikipedia maintainers and the Stormplay developers).
I'll always have a special place in my heart for IRC. This server isn't used much, it's mostly been replaced with Matrix, but I still have some monitoring software that checks in there as well as some bots for work. It's open to the public and also has two web interfaces (The Lounge), one of which allows guest users.
I'm interested in bringing new tech like ActivityPub and federation into the mainstream, as well as ensuring old tech (RSS) is used to it's fullest. This project is a public Lemmy server, which is populated (at least, I hope, initially) by RSS feeds from blogs and projects from around Glasgow. I also plan to mirror posts to a newsgroup server, but I'm still working on that. You can check it out at https://lemmy.glasgow.social