Mochimarks has configurable reminders, wishlisting, bookmark ranking, opt-in sharing, and can recommend bookmarks it thinks you might want to read again. Mochimarks also has the features you'd expect from an modern bookmarking website, including tags, read later, full text search, responsive design, and lots of sorting options. I've tried hard to pay close attention to security and privacy. I'm still working on batch editing bookmarks.
The easiest way to interact with Mochimarks is via its chrome extension. Otherwise, there are bookmarklets. I know the online bookmark space is crowded, but I've personally found the features I've added really useful. Thanks!
Also are you doing this as a toy project or is this a business?
I plan to charge once I'm done with the beta, but it would be more of a side business. It started out as a toy though, so who knows what'll happen long term.