I miss directories. The hard part is to keep it up to date and delete unreachable sites. Also flag the inactive ones. I don't know if this site does this.
It's currently possible to filter each category to only show blogs that have been updated within the past week/month/year, which should help.
If it gets to the point where there are lots of blogs that are still live, but haven't been updated for a long time, maybe I'll make the default to only show blogs that have been updated within a year or so. We'll see.
I can see which blogs generate errors of different kinds when fetching their feeds, so I'll be able to spot blogs that disappear. If that happens they'll be removed/hidden from the site.