The global outage drinking game:

bad DNS config push - 1 shot

routing loop - 2 shots

third party advertising your routes - 3 shots

power outage at data centre it turns out everything depends on despite decades and millions in engineering to avoid precisely that - 4 shots

Wolves ate through fiber - 5 shots

And it was a full moon - 6 shots

Single service failure, but service has not been restarted in 5 years, and no longer restarts in any documented fashion - 7 shots

And service developers left the company to found a startup - 8 shots

Expired internal SSL certificate - 9 shots

Daylight savings changeover-induced database corruption - 10 shots

Windows Update - 11 shots

Probably DNS. It's always DNS ;)

Large scale network partitioning can happen. Data center ingress/egress can go down. If you shard to multiple data centers, it's still possible for an entire autonomous system to have an interconnect with a different AS break. That is rare as hell with the actual Internet because of all the route redundancy even between ASes, but I've seen it happen on more specialized networks. For a few days last year, the entire western half of the US was cutoff from the eastern half on Raytheon's internal TS network because someone digging a hole somewhere accidentally cut the wrong fiber line.

DNS (not necessarily this case, but man it can bring things down fast)

How does it stay up as much as it does :)

I'll be curious about it coming back up. It's the sort of site where there's an army of people continually trying to reload the page if something isn't working.

Probably an intern doing something dumb.