There should be a way to undelete articles, or no way to delete them: currently, deleted articles are still visible from the feed, and it's possible to comment on them, but otherwise they are in limbo: they are not on the sidebar or any other list of articles, and there is no way to restore them.
[Edit: Issues, Bugs, and Requested Features should be tracked at Google Code, not here -- matt, 2010-04-23]
Less Wrong is still under construction. Please post any bugs or issues with Less Wrong to this thread. Try to keep each comment thread a clean discussion of each bug or issue.
Requested features... sure, go ahead, but bear in mind we may not be able to implement for a while.