Feeds4All is a generic blog directory, and of course some of these blogs are actually podcasts.
It has a moderately effective though still overly generic set of categories with which the blogs (and podcasts) are categorized. The categorization is two-level, with major categories and with each of those a set of secondary categories.
Once you've found a blog/podcast to look at you have a page giving a summary of the items, each of which also live on their own page.
The focus is browsing "feeds".. a feed being either RSS or Atom, and of course either one can be either a blog, a podcast, or even a newspaper, or nearly anything. But the set of feeds they track is "moderated" so apparently you can't track newspapers or any old random feed with this site. Only the ones the site approves of. For that matter there isn't any membership arrangement, so the activity the general public has is to browse around the feeds and find stuff to read.
A sister site, FeedAlley has a user registration system, and the users are free to add tags to feeds. The tags act as a way to more effectively browse the available feeds and postings.
Another sister site, FeedGarage has some unknown purpose. Both of these sites are said to be in development, and we are encouraged to stay tuned for further developments.