After a software update and reboot together with some system tweaking, my personal webserver was not loading httpd successfully. I checked /var/log/httpd/error_log and found this: "[alert] mod_unique_id: unable to gethostbyname" followed by my hostname – actually, the hostname I had specified when setting up my server.
I had changed the Rendezvous name in Sharing Preferences, and forgotten that my hostname would be changed too – this conflicted with settings in httpd’s conf files. For now, I’ll just switch off the unique id module in Server Admin under Web service.
Web service is back up.