If you have multiple systems (like I do), a problem you've undoubtedly run into is keeping your bookmarks in sync across every browser you use. Of course, there are services that'll happily do this job on you behalf, but they're free, and we all know what free means. If you're interested in being social with your link collection there are some social bookmarking services out there for consideration, including what's left of Delicious. For many years I was a Delicious user (because I liked the idea of maintaining a public bookmark collection that could be useful to people), but Delicious got worse and worse every time it was sold to a new holding company. I eventually gave up on Delicious, pulled my data out, and thought long and hard about how often anybody actually used my public link collection. The answer wound up being "In all probability, not at all," largely because I never received any feedback at all, on-site or off. Oh, well.
For a couple of years I used an application called Unmark to manage my link collection, and it did a decent enough job. It also had some annoying quirks that, over time got farther and farther under my skin, and earlier this year I kicked Unmark in the head and started the search for a replacement. Quirks like, about half the time bookmarks would be saved without any of the descriptions or tags I gave them. No search API. The search function sucked so I couldn't plug my own search function in. Eventually, the Unmark hosted service started redirecting to the Github repository, and then even that redirect went away. Unmark hasn't been worked on in eight months, and Github tickets haven't been touched in about as long. In short, Unmark seems dead as a doornail.
So I migrated my link collection to a new application called Shaarli, and I'm quite pleased with it.