Scoble accidentally remarked on an old news item, because his reader saw old content on the Google Blog as new stuff:

this post originally appeared in 2005 (I didn’t remember it from back then). Turns out that RSS kicked out a new version of this post. Both Bloglines and Google Reader users saw it again (that’s where I saw it).

Over the last two days, I've seen a ton of old stuff show up as unread in BottomFeeder. I've seen this kind of thing before, and it usually means a change in the content management system (and thus, all new GUIDs).