At the moment I've only added blogs that have been updated within the past year or so. But over time some blogs will obviously stop updating.

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.