Some lucky people might be able to create global accounts at the moment,
but please note the following caveats:
1. Local access control on account creation is largely broken. The new
user log, IP blocks on account creation, and AntiSpoof conflict checking
are broken. Only private and fishbowl wikis are still protected.
2. Email address changes are local and don't propagate properly to the
other wikis.
3. There's no cookie sharing so you have to log in to each wiki separately.
4. There's no shared preferences except password
5. You can't rename a global account.
I intend on fixing items 1 to 3, in that order. I won't make any
guarantees for 4 or 5, maybe someone else is interested in them.
-- Tim Starling