I currently operate two of my own blogs, this one (obviously) and The Starved Writer, where I decry the state of the writing industry and its meager standards for survivability.
Both of my blogs have been in operation for about nine months and during that time they have each seen steadily increasing page views month over month. To accomplish this feat I rely upon my experience as a social media manager, leveraging my network to promote each of these sites to audiences who I believe will find them interesting, including the use of social bookmarking sites.
Bookmarking sites are one of the many of tools I use to target my blogs to audiences interested in reading them. Bookmarking sites are crucial to all bloggers because they are used primarily by Internet surfers who are interested in reading blogs and articles. In other words, the millions of people who go online just to read stuff, use bookmarking sites to find the content they are looking for.
Myself, I use Digg, StumbleUpon and Delicious to bookmark my articles, tag them appropriately, and promote them directly to people looking for that type of content. There are plenty of others, of course. Sites like Reddit, Fark and DZone do something similar, but they are a little too tricky for me to navigate, so I avoid them. My time to produce and promote my blogs is limited so I look for methods which make it as easy as possible for me to do what I need to do and move on to something else.
Combined, these sites produce an additional 100 or so page views every day for my blogs, directly. It is difficult for me to judge exactly how many additional visits I get when someone passes a blog post they like to someone else in their network (simply because I am too damn busy to do the analytics work required to tell) but it is safe to assume it is an additional 50-75 percent, judging by the response I get when I use them.
It is worth repeating that these sites are designed to be used by people who regularly read blogs and articles. Their core audience is comprised of exactly the sort of people I am looking for: readers. These aren't people who might just happen across a link to my blog (such as when I post a link to Twitter or Facebook) they are people looking for blogs to read. That means they are already actively looking for content so when they happen across my content it already fits one of their criteria for clickability: It is something to read. By marketing directly to them I am giving them what they are looking for. I am not trying to push them into something new and this key to their effectiveness.
If you have a blog, or if you are thinking about starting a blog, be certain you find at least a few (if not all) bookmarking sites to promote them on. This will not result in a huge influx of readers overnight but it will likely gradually increase your audience by marketing directly to the people most interested in reading online.