This is a refreshing example of Owning Your Mistakes. Tumblr Inc. not only admitted their error, they took the extra measure of making sure every customer knew about it by linking to it from the Dashboard.
Owning your mistakes is a cornerstone of being a business (or person) of integrity, and it comes as no surprise to me that David and Marco are practitioners. Thanks, guys, for striving for perfection without pretending to have achieved it.
