I use delicious for 5 years and keep a local, sync copy to make it possible to program, so that I can develop my own desktop tools.

I mean, a free Pinboard was a solution for me when I was looking for a good alternative of delicious, 2 years ago.

But it's not free. The owner claims that he'll keep maintaining forever but he will not when he lose a considerable percent of his customers.

And he'll. As I said, pinboard solves the wrong problem. An online bookmarking service can be structured in a way that will cost nothing. Couple of scripts that manipulate a text file on DropBox was the solution came to my mind in 3 seconds.