Domainmonster.com Domain Editorials
Most obviously, sites can be bookmarked publicly. This means that sharing bookmarks with friends and colleagues is far easier, as emailing links becomes a thing of the past: they can simply view your page of links and select the ones they want, adding them to their own lists if they so desire. What is more, many sites have a group creation feature, so that groups of individuals can share and aggregate their own link lists. This is especially beneficial for business users, as often groups can be made private (so individuals must be approved before they can join, or need a password to add links to the group). This means that only the links relating to the specific needs of the business will be shared.
Another important feature of social bookmarking is the ability to "tag" entries with whatever words or phrases the user desires. As many tags as the user likes can be assigned to an individual link. This is a way of categorising which does not force the user to choose a single folder or category in which to place each link; a link could have the tags "floristry", "rose", "yellow" and "red", whilst another might have "floristry", "carnation", "red" and "pink". Some social bookmarking sites will show these links as being related because they share some tags. If a user views all the pages which are tagged "floristry", they'll see both links; but they can also narrow down their interest and just look at links tagged "carnation". What is more, links can be aggregated. It is possible to view all the links that anyone has tagged "floristry", or just those users in a particular group. Users can also view which other users have bookmarked the same pages, and may find other bookmarks by these "related" users to be useful.
Basically, social bookmarking creates a network of bookmarks which are connected by category and by the preferences of individuals. Diigo is particularly recommended because of additional functionality, including ease of searching, and the ability to highlight and annotate web pages.