Every server is down every once in a while, and your certainly want to know what happened if it hosts one of your favorite sites or one of your own ;) A good example on this front is Dreamhost’s status blog, where Dreamhost publishes every single server maintenance task (at least as far as a lowly customer as I can tell).
sw-guide.de had now a similar idea: Shouldn’t there be something like that for weblogs that are down or are planning a downtime? So they created http://blogwartung.de.
Apart from status updates, in the future this blog should also contain tips for webmasters on how to deal with problems on their blogs. Nice idea :)