It was already dead by then. Really, it was the various Slashdot exoduses... sites like K5 got large initial boosts, but stumbled and started to deteriorate. If the Digg exodus is what sent you to Slashdot, chances are you're the kind of user everyone else was trying to escape.

>what's the alternative to Reddit? I mean, it's certainly not Quora.

If it was deliberate I certainly can't tell, but one of the characteristics of Reddit is that it caused so many other little tiny internet forums to just wither away. Most were visually unappealing, running some ancient phpbb software or whatever, but there were so many like stars in the night sky. Now, if they're even still running, you look for the newest post, and it will say "November 2023". Hell, the only reason they are still running is that the credit card number on file paying for hosting doesn't expire until next year somehow. Reddit is a red tide algae choking out all life in the ocean, nothing else gets to exist anymore.