Unlike other social media platforms where people use them primarily to
network with other people, the communities that comprise social
bookmark sites are interested in finding websites that appeal to them.
The simple process of sharing websites is what makes social
bookmarking such a powerful tool in a marketer’s arsenal. As long as a
marketer’s website provides useful content, an interested visitor could
bookmark that site and bring people with similar interests to the same
website.

The ability of users to “tag” certain websites also adds search engine
value to social bookmarking. These tags will help make your website
more attractive to search engines if enough people bookmark it; helping
raise your ranks on the search engines.

So the big picture with social bookmarking is to connect with people that
share similarities with your existing followers and customers. The added
visibility on search engines are a side effect of being bookmarked by
people, but it is still a welcome side effect.