In the 1989 movie "Field of Dreams," a corn farmer hears voices telling him to build a baseball field. The voices say, "If you build it, they will come."
Unfortunately in the world of startups and technology, often people build it, but no one comes. The missing element for these ventures is effective marketing. If no one knows about your great invention, website, or product/service, no one will use it or buy it.
The process of marketing new ventures was revolutionized in the past decade with the advent of the Internet, and specifically search engine optimization and advertising on sites such as Google, Yahoo, and MSN. Such advertising gave ventures the opportunity to quickly and cost-effectively reach thousands of targeted buyers/users.
Fortunately, a further evolution in new (and established) venture marketing has emerged.
The driver of this evolution is "social news gathering," a process whereby Internet users find information, rate it and share it with others using established platforms. Such platforms, also known as social bookmarking sites, include Digg, del.icio.us, Furl, Reddit and StumbleUpon among others. This evolution has resulted in a new marketing discipline known as "Social Media Optimization," which is the art and science behind getting your company's news to rank highly on these platforms. 
Let's look at how such sites work using Digg as our example. If you visit a web page and like it, you submit the story to Digg. Often sites have icons such as the ones to the right, which link directly to the article on Digg.
Once the story is submitted, it is posted in Digg's upcoming stories section which is read by Digg members. If enough Digg members digg/promote the story, the story gets catapulted to Digg's homepage. Once here, thousands of people will read the summary of the story. Furthermore, many of the people who read the stories on Digg's homepage are bloggers, who, if they like the story, might write about the story on their own blog, thus making even more people aware of it. As you can see, a Digg-worthy story could quickly reach a widespread Internet audience.
Regarding Digg and other social media sites, it is important to note the following:
To get noticed on Digg or other social media sites, your story generally needs to be sensational. No one cares about a press release introducing a new company or a new product you have launched. Spend time on Digg and the other sites learning what each community finds interesting and tends to promote.
Don't try to game the system. People have tried to, for example, create 1,000 Digg accounts that incestuously Digg stories. Companies like Digg are smarter than that and have safeguards to avoid manipulation.
If you're not convinced of the power of Social Media Optimization, maybe this article  entitled "Anatomy of a Super Digg" will convice you. The article describes the distribution of a report entitled "8 Diseases That Give You Superhuman Powers" that, through social media optimization, was able to drive 234,000 unique visitors to the author's website within five days.
Digg recently enrolled its one millionth member. If you haven't already joined, you may be missing something big!