Inter Wiki is the idea of linking wikis together.
Historically, the term referred to having one wiki, distributed across several servers; See:Distributed Wiki, One Big Wiki (Switch Wiki), Wiki Web Transfer Protocol, World Wide Wiki Web, Multi Server Wiki
Over time, Inter Wiki has come to mean connecting existing wiki, of various Wiki Engine types, together.
The idea has expanded even beyond wiki: Connecting all willing communication systems together into a gigantic mesh of software. See Int Comm wiki, Web Services, Web Services Discussion.
Inter Wiki organizing happens all over the web. Many wiki and mailing lists contribute substantially to Inter Wiki efforts. Wiki include Meatball Wiki (www.usemod.com 
), Community Wiki (www.emacswiki.org ), and the Inter Wiki Wiki (www.communitywiki.org ).
Not all Inter Wiki work is technology work; Some of it is purely social (introducing sympathetic wiki communities to each other) - like the Tour Bus Stop project, some of it is standards based (Wiki Nodes; cc.msnscache.com ), some of it is legal. (wikilegal.wiki.taoriver.net )
Alas, two wiki – “Wiki Futures” and “Wiki Legal” – are offline as of 2008-03-11. In a couple of months, if they are still offline, please delete those delegations.
Work on Inter Wiki technologies and conventions has been in effect for a long time now. Sister Sites and Inter Wiki Links have been around for a long time.
New linking technologies such as the
(wikifeatures.wiki.taoriver.net ) were introduced in at least 2003
Many more technologies on the way.
Page transfer standards, independent of wiki syntax, is underway. And a lot of work on a
Wiki Syntax Standard has been underway for a long time now.
It is clear that Inter Wiki technology has been delivered, and is continuing to be developed, and will expand in the future.
The future appears to be less Inter-Wiki and more Inter-Net.
What has been called wiki appears to be becoming the document arm of PublicInternet Communication, meshing with threading friendly systems, blogs, identity services, resource sharing, and existing online communities.
See original on c2.com