The article lists several lessons learned from this, but really there's only one huge issue: stop using GET to modify state that the user cares about! Use POST!

The article lists several lessons learned from this, but really there's only one huge issue: stop using GET to modify state that the user cares about! Use POST! It's not hard! Or rather, it's less hard than dealing with the subtle problems that crop up when you use GET when you should have used POST.