When I tried to login to our Salesforce.com account this afternoon, I was greeted with this: 

After a few more attempts and waiting a number of minutes for the issue to resolve, I went to Twitter to see if anyone else was experiencing the same issue. It turns out that I wasn't alone.

Digging further, I found the following explanation on Salesforce's status page.

What was the culprit? A database script.

I feel for the person or team who missed what I'm sure was an error in a small line of code.  It also serves as a reminder that manual manipulation of data within a database is inherently risky.

This is why we're not eager to adjust your data using SQL scripts and will often work hard to find alternative ways of accomplishing your business goals.  It's also the reason that no matter how small the change, we will always budget at least 2 full hours of engineering time to execute any database script that a customer may request us to run.