With Pinboard down recently[0], I have made a pledge to myself to export from Pinboard.in as frequently as possible to a local hard-drive where I then back that up in several cloud locations for peace of mind. As a rule of thumb: I don't build my castles on other people's land. Edit: the cloud is building castles on other people's land, but I have local backups and don't put all my eggs in one basket (i.e use several providers like Backblaze, Dropbox etc).

[0] https://news.ycombinator.com/item?id=29873306