Your experience on the site is largely determined by what sorting algo you use by default, IMO. (or what mega you browse if you primarily hang out in the megas)

If you use Hot sort you will see mostly new posts, but comments sections will be pretty empty. If you use Active, you'll see the posts with the most active comments section, but they'll all be like 12h to 2 days old. Etc.

So using Hot (or especially New), the comments can feel really empty: but you have the opportunity to be the one who starts the interesting discussions in the comments, or gets first dibs at the cheap jokes. Using Active you'll see the fullest comments sections and most struggle sessions

You can try both of them out using the selector on the front page, but if you want to change your default that's on your user settings page (in case it wasn't obvious)

I switched to Hot after we migrated and federated, but it took me a while to realize how drastically different the site experience was on Hot vs Active. I still default to Hot but sometimes I switch to Active to see slapfights or good posts that I missed

EDIT: Also to provide some data, our monthly active user count is actually up ~200 since 6 months ago. That's something like 10% growth? These things are hard to really judge precisely but I don't think there's any sign we're dying