The general goal is to allow auto completion in Wiki and WYSIWYG editors for inserting links, images, macros and more. In practice you'd start typing some characters and you'd get a completion list as you get in Java IDEs for example. Here's an example: you start typing "[" and you get a list of documents to which you've recently navigated to, you continue typing letters and the suggestion lists narrows to documents containing this letter, etc.
One goal is to make the WYSIWYG editor as fast to use as the wiki editor.
For details see http://jira.xwiki.org/jira/browse/XWIKI-206
See also the implementation done by Confluence: http://confluence.atlassian.com/display/DOC/Confluence+3.2+Beta+Release+Notes
In addition a secondary goal could be to support wiki syntax in the WYSIWYG editor (for example with an option to activate the wiki syntax mode for a given syntax). In this mode if the user types, for example, "*hello*" then it's transformed into bold. This would allow to benefit from the best of both worlds.
To summarize the general goals of this project are:
Speed up content editing in both WYSIWYG and Wiki editors
Make the wysiwyg editor attractive to advanced users too and make it approach the speed of the wiki editor