How does someone the size of Reddit, go down?
Imagine you're Reddit, you do down, like it is right now, thousands of reports in the last few minutes. How can you be that size of Internet company and not have the ability to stay up, resilient to most outage scenarios?
One minute of their downtime loses about $5k - $10k of ad revenue.
One year of massive redundancy costs (tens of) millions of dollars, and will always be slightly susceptible to failure anyway.
... and productivity skyrocketed. :)