Facebook  is the world’s largest social network, with over 500 million users. The website was offline for a few hours on 23rd September 2010 due to a technical problem. Several jokes about the Facebook outage were soon streaming on Twitter, with many of them being re-tweeted by hundreds. A few are shared below:
While Facebook Isnt Working, Twitter will go over capacity, (and MySpace remains unused,) some Americans will finally meet their neighbours.
I shut down facebook. That'll teach The Social Network for trying to steal attention from the Deathly Hallows Trailer. Take that, Zuckerberg
Facebook is down. We can't tell who's hungry or tired.
i love the way @facebook has to use @twitter to tell everyone why it isnt working. #fail.
Facebook is down! Employee productivity skyrockets, rioting reported in major cities, USA climbs out of 6-year recession
DNS FAILURE: Facebook is down which means 9 months from today, many children will born.
#facebook is down. Not sure if we did that, but we should claim credit anyway. Hitting the infidels where it hurts, etc
@Facebook  posted the following updates on Twitter during and after the outage:
We apologize for today's outage. Read technical details about how it happened and how we've been fixing it: http://ow.ly/2J5dA 
We've resolved the tech issues that caused the site to be unavailable for some people. Everyone should now have access.
Facebook may be slow or unavailable for some people because of site issues. We're working to fix this quickly.
Facebook has since apologized over the outage :
Early today Facebook was down or unreachable for many of you for approximately 2.5 hours. This is the worst outage we’ve had in over four years, and we wanted to first of all apologize for it. We also wanted to provide much more technical detail on what happened and share one big lesson learned.
The key flaw that caused this outage to be so severe was an unfortunate handling of an error condition. An automated system for verifying configuration values ended up causing much more damage than it fixed…
Some Mashable readers are more sympathetic with Facebook,  about the outage:
In a comment, fpd wrote :
I never get the public outrage anytime something like this happens. It's the Internet, no site is safe from these types of issues. A lot of code goes into these sites and expecting 100% uptime is ridiculous. It happened to Google with Gmail, happens to twitter all the time, it probably happened to Yahoo! or Bing recently too and no one noticed. If you are honestly that dependent on these apps that if something happens to them you are screwed, you need to consider a backup plan.
Sakima Oak added his view :
Every website experiences problems but a website the size of Facebook and to be resolved and back online in less than 4 hours is incredible.
As Neale had mentioned, a custom system built from the ground up on PHP and I can't think of any other website that compares. Well done Facebook techies ;)
I would wrap up with this rather humorous view from JayNerd :
Facebook goes down once every four years.
Twitter still goes down every four hours