Ask HN: Why did delicious.com fail? (2017) https://news.ycombinator.com/item?id=15493212 After some digging, the above thread seemed like the most informative one as to what happened to Delicious (with a top comment from joshu, no less).
> we concluded that it would be quicker to re-write the app as opposed to dissecting the exiting application codebase. This is the primary reason why stacks were canned, regardless of what others might have said. Many times rewrites require reducing features in order to build a new foundation. This is sometimes a good thing, and sometimes not.
And then the pinpoard guy just summarizes the frustration of countless users:
> But the biggest mistake was when AVOS turned off some features beloved by a core Delicious constituency, fanfic authors. In particular, they made it impossible to search on the "/" character in tags, which instantly rendered a lot of the elaborate fanfic tagging and classification scheme useless. In my mind, that's when Delicious hit the point of no return.