Have you noticed that when you go to Amazon, it drops you into your “plog” by default? It mostly has recommendations — it’s interesting to see the explanations of why they’re recommended — but it also has “pending activity.” For example, I ordered a couple books a week ago, on July 11, and for that day, there’s two entries for each book I ordered.
I’m an Amazon junky, so maybe my view is skewed, but that’s pretty neat. Hopefully they’ll add more stuff into it. It’d be especially interesting if there were RSS feeds for all the plogs so you could see what your friends were up to.