Feed explorations
All LiveJournal test users now have Atom feeds. Here is an example. I happened to pick one that was in Russian, demonstrating the use of UTF-8. Also notable is that issued dates don't have time zones - something that LiveJournal doesn't track for this particular field. I'm particularly looking forward to the point in time when LiveJournal starts exploring the serialization of threaded comments.
Simon Fell's Atom feed demonstrates explicitly marking the namespace on every item. More interestingly, he makes use of xml:base to have relative urls in links, ids, and even content.
Gordon Weakliem has created feeds for Amazon.com, and is exploring issues with dates and times.