It appears a number of dodgy links appeared in my Lifestream originating from Delicious and dating back to 18/19 September. Unfortunately I’ve only just noticed them. By the the time I checked Delicious, none of the links were still present. None were posted at the time I bookmarked anything else, so it doesn’t look like a browser hijack. The only coverage I could find suggested than somehow the RSS feed was hacked, which makes sense from how it manifested. If that is the case I hope the fix is permanent. After trying other social bookmarking services I keep coming back to Delicious. I’d hate to have to give it up for good.
The links have now been deleted from the Lifestream but I expect they will linger in a Google search for a while.