Federated wiki sites are launched on demand using Wildcard DNS. You can enter any subdomain that isn't already taken into the URL bar of a new browser window. For now, claim using your google credentials or read and write in public anonymously on unclaimed sites.
Double-click on page content to edit it, beginning with the word 'wiki' on the nav bar below.
[+] to add more writing spaces.
To share pages between sites, drag colored squares between browser views and ⚑ to fork.
See Field Guide to the Federation or How to Wiki for more options.