I have a few domain names, including firstnamelastname.co.uk. I mostly use it for spam monitoring; everyone gets a different address, so eBay has ebay@, Microsoft has microsoft@, etc. It's harder for them to link my identities together and if I suddenly start getting fuckloads of spam I know who leaked/sold my address. Fuck you, LinkedIn and LastFM.

I also had my own email server until recently (MailInABox on Proxmox), but I was looking for a cloud storage provider so I ended up signing up for Proton and moving my email there.