Following a security issue on the server hosting the xkcd fora and wikis, the main geohashing website has been down since September 2019.
At present, it is unclear if an when the geohashing wiki will be back. Efforts to bring back a central location for sharing geohashing information are being discussed on the official IRC channel on slashnet. Connect using your favorite IRC client or a web client
If you would like to be involved but don't want to follow the IRC channel, you can drop a line to user:crox using the contact form at https://ssl.crox.net/contact/
You can still go for hashes, coordinates can be found using the various calculators: