The post counts used to display next to each category and sub-category.
The widget's still working for me, but about a month or so ago, perhaps after upgrading to MCO 2.8.6, the post counts stopped displaying. I waited until 2.8.7 came out but there's been no change. I am running WordPress 2.9 now as well.
I don't see anyone else mentioning this. Was there not a change? Can something be edited to get them showing again?
I did try adding 'show_count=1" to wp_list_categories but that wrecks the whole plugin, so that's not it.