- Cached snapshots
- search bookmarks by actual boolean operations on tags, which is something hardly anyone does for reasons I've never understood.
- Fast, simple website. Everything that was good about 1999.
- Browser integrations for every browser worth mentioning
- OS integration for quick search outside of a browser
- mobile apps aplenty (i use Pinner on iOS)
- fully private bookmarks, if you want (which I do)
- nice API (I have some silly python scripts that give me tag statistics and clean things up; they took about 20 minutes to write)
- it's a one-man show, and he answers emails!
- tarball-of-all-your-data on demand.