"Slash fic, or fan fiction about romantic relationships between popular characters, is traditionally denoted with the / mark it takes its name from. E.g. Steve Rogers / Bucky Barnes, or Hermione Granger / Harry Potter. The AVOS redesign made it impossible to tag or search for anything with a / in it. A single symbol turned into a huge opportunity for Delicious’ growing rival, Pinboard. "
It's the little things that get you. An important lesson wiser people taught me. One of the reasons I favor good QA followed by trial roll-outs with user feedback. They might have saw this problem popping up a lot. A quick poll or question about the design detail might have showed the impact. Then, they could've avoided it.
Instead, top-down, ignore-the-users management prevailed. That earned certain results, too. ;)