This definition is deliberately recursive, because the more BidirectionalLinks are between two wikis, the easier it is to "make new friendly connections". There are different reasons for this:
WikiWeaving is done by: Wiki authors, supported by appropriate technical infrastructure and the goodwill of the wiki providers to allow deep linking.
As an example, this page is a
TwinPages, UnifiedRecentChanges, MetaWiki are some tools to aid WikiWeaving. TwinPages, for example, finds pages with similar titles on "sister sites", ie. sites which provide a list of their page names in a retrievable form. See Wiki:SisterSites.
Some people have suggested providing an easy interface to search engines such as Google, possible a "Google:" prefix which searched Goggle but looks similar to InterWikiLinks.
Some people have been using CritOrg to bridge several Wiki pages, such as not to disturb the base discussion with "WikiOnWiki" things. This is potentially problematic because it may go against the WikiWay: No ForgiveAndForget, 100% ThreadMode, if the CritOrg authors don't edit and delete accordingly. For more info, see CritLink.
Integrating other wikis gets easier.
New wikis might fill up with references to other wikis without providing their own content, without their specific take on things. We might loose the community aspect of Wikis, because only one page of all the TwinPages will accumulate critical mass of good content. Thus, let us do just that -- point or redirect automatically to the "main page" and delete the TwinPages.
Old wikis will loose focus because TwinPages encourage to link to other communities, thus the borders disappear and people migrating in from other communities unconsciously (ie. no lurking and learning on their part) make an editor's job harder.
A major point of WikiWeaving is to directly point from one wiki's pages to another wiki's pages especially when you want a link to content that does not really fit into the source wiki. In that case, you already have better content in the target wiki, so instead of making an inferior local page, you refer to a better outside page. This is a win-win situation, since bot wikis get more cohesive with regard to their topic.
Perhaps extending the Wiki mode in Emacs or XEmacs might be helpful, because Emacs allows the comparatively easy implementation of custom clients (there are web browsers and wiki modes, web servers and lots of other tools written for Emacs). See EmacsWiki:WikiModeDiscussion, EmacsWiki:FridemarPache.