I’ve found out how to create an RSS feed for your lifestream (don’t add this to your lifestream – it will create some kind of MC Escher moment). Just useful if you want to subscribe to your own or someone else’s lifestream in your RSS reader!
It is in this format (replace ‘jenr’ with your own username):
http://digitalculture-ed.net/jenr/feed/?feed=lifestream-feed
It’s a bit dodgy about when things were posted, but otherwise seems to work pretty well.