Aside from other hacks, this one looks like a true categories integration to Blogger
I saw this commenter (named Craffter) post in Blogfresh :
My god, brilliant work...so this is it... true blogger categories...man oh man... now we can have 2 kind of categories if wanted, and if we just add a category counter, we can have the numbers of post displayed on them.. tags, listing categories, true categories...awesome stuff.
This comment was about Labelr , a service that integrates categories to Blogger. Unfortunately, Labelr is in closed testing so I can't say much about it other than what Blogfresh reported.
It's pretty exciting to have a solid third-party support for Blogger because it keeps the service very functional. Well, until Blogspot adds their own categories, I'll be watching Labelr closely .