I'm tagging this Kinja Help because if the sidebar was behaving this way yesterday, I didn't notice and whether it's working right or not, I thought this worthy of a heads-up.
When looking at the Crosstalk index page, I get the sidebar which follows the pattern we've known (current, "popular" posts), but if I click through to individual posts, even though they are from Crosstalk, I'm seeing the sidebar which is the personal for the author of that post.
For example, right-click the Crosstalk logo text and open it into a new tab. Compare that sidebar to the one which is to the left of this post.
Update: Here's a link to Lauren's post. Though it really doesn't include anything that isn't covered in the thread, below. (Also, the Kinja Help tag has been removed)
2nd Update: It looks like the same functionality has been applied to the ad-supported blogs and if a blogger hasn't recommended any posts, the sidebars on their own will be blank. This is the same as it works with community bloggers, so apparently it's not broke.
3rd Update: Lauren has confirmed this to be the case.