I need to be able to retrieve Wiki articles using the XML API and a token from a community user. The very same community user has access to this wiki via normal FB interface, so it seems strange that he or she cannot access the articles via XML API.
I know the history of that... quite a long time ago, to be exact on February 29th 2008, a security problem was found in FB6 with community users and the XML API - in consequence, the XML API access was disabled for community users (and the problem in general was addressed and fixed as well).
However, with the release of V7 and the updated API as well as the new plugin APIs, it's very inconvenient that one cannot access the XML API via a token of a community user, and I don't see a real reason for that.