The many widgets and tools available today makes it very simple to provide social bookmarking tools for content on websites. This makes it simple for visitors to your site to share your content with various services - Facebook, StumbleUpon, Digg, and hundreds of others.
And while this can be really useful, it's more geared towards spreading content. It's more about marketing. It's very external-facing. The term social bookmarking is interesting too. While it certainly functions as a bookmark, it's different from other definitions of the term and previous uses of "bookmarking" when it comes to the web.
Thanks for the reply, Matt. I'd like to add to your explanation that one key to how the pet...