As of this writing, Bill Oakley has 3,660 followers on Twitter.  Last week, he tweeted the following, innocuous Season 7 quote:

Since Oakley’s followers (the ones that are real people who actually follow their Twitter feeds, anyway) are fans of the show, they responded with some of their favorite Simpsons-related telephone gags.  Here they are (and remember that it’s Twitter, so read bottom to top):

According to Twitter, it was twenty-six minutes from Oakley’s initial tweet to the one where he thanks everyone and says he can’t keep up any longer.  In that time he retweeted fifteen quotes or references to telephone gags that had been on The Simpsons (including two from our old friend Steve of “In 10 Words”).  If you’ve read the tweets then you already know where I’m going with this: not a single one came from after Season 9. 

Obviously this is not a scientific sample of popular opinion complete with a margin of error.  But as an observation of real people interacting with each other it’s very telling.  All Oakley had to do was type “Ahoy-hoy?”, and everyone instantly knew that it was a Simpsons telephone gag.  He was then bombarded with so many responses in kind that barely an episode’s worth of time later he had to thank everyone as a polite way to ask them to please stop.  Every single one of the responses was from episodes thirteen years old or older. 

In a nutshell, that’s the lasting difference between The Simpsons and Zombie Simpsons.  More recent episodes, which in theory should be fresher in people’s minds, have been all but forgotten.  But even after more than a decade, the old ones are so good that random strangers on the internet still want to quote them and laugh at them.