Most services you might use to save links for future reference or reading are part social network and part sharing service. They're designed to help you share those links, or make big lists. LinkLocker is none of those -- it's completely private, and the only person who can see your bookmarks is you. It's perfect.
LinkLocker just emerged from private beta (which, full disclosure, I was a part of), and it's great if you're doing research and don't want the world to see your bookmarks for whatever reason (maybe you're looking up gifts for someone, studying security topics or just want to save all of your... research findings for future reference). Once you sign up, you can add a bookmarklet or extension to your browser (available for Chrome, Safari and Firefox) to make saving sites to your LinkLocker account easy.
From there, log in at any time to see your whole list, organise them with stars or tag them by subject (or anything else you like) or delete any you no longer need. The service has built-in search so you can easily find anything you've saved quickly. Plus, your data is yours, and you can export all of it at any time.
Of course, if you need the social and sharing features of other services like Xmarks or Pocket, you should absolutely use them. I don't see LinkLocker replacing them, or even competing with them really -- but if you want something a little more private, it's a great option. Of course, a service like this with a focus on security that's also ad-free has to make money somewhere, and that's where its subscriptions come in. They're $US1.50 ($2)/mo or $US12 ($16)/yr, which isn't much if you've read this far and are interested. Hit the link below to read more about LinkLocker and its features.