Is it open source and self-hostable? At this point I no longer trust these kinds of services since they always seem to be abandoned, suffer from enshittification, or just degrade. I need to know I can migrate easily once it happens.
I use pinboard every day, have done so for a decade and it works exactly as intended.
The fact that there have been no recent new features troubles me not one jot, my keyboard hasn't had any recent new features either, it just works.
Judging by the last time pinboard was mentioned on HN, https://news.ycombinator.com/item?id=34062802, the 'archive' feature, which is a 'pay extra' feature, causes dissatisfaction amongst some people, I can't comment on that as I don't use it.
Pinboard is run by a single person so if you're a user it would be sensible to use the 'export' function from time to time to allow for the owner getting sick etc.
My pinboard account still works fine too but I moved to raindrop.io recently because it's the same thing as Pinboard, done better, with apps, and a dev that cares.
Might not be abanndoned but it's certainly in "fend for yourself" mode.
If you sign up for Pinboard at this point and expect new features, then it's on you. I pay for uptime and maintenance. (Paid in 2010, 11k bookmarks, very satisfied.)