[Social Media means] "Internet way-finding tools informed by human judgment. 'informed' can mean many things including egregiously uninformed." Chris Sherman, Executive Editor: Search Engine Watch @ SES Chicago 2006

Social Media Optimization (SMO) sites publish or index content by way of differing information dissemination models. These are appropriate and potentially useful marketing channels for many advertisers and overlap traditional public relations (PR) channels.

The Internet's roots are in social search. The first search engine indexes, including Yahoo®, were moderated by humans interested in sharing editorial feedback on website content. When meta tags were introduced in 1996 spammers wrecked it for everybody. The experiment, designed to give webmasters a technical method to inform search engines as to a website's content, was a horrible failure.

Now the social component is becoming prevalent in search once again. Link-baiting articles, blogging, collaborative directories, and Q & A sites have become legitimate (white hat) methods to grow organic search engine listings (SEO), generate spikes of traffic, and garner high quality inbound links.

Social search sites can be generally categorized as follows:
Shared bookmarks and web pages (del.icio.us, shadows, furl, myweb, diigo)
Tag engines, blogs and RSS feeds (technorati, bloglines, feedburner, wordpress)
Collaborative directories (prefound, zimbio, wikipedia)
Personalized verticals (eurekster, rollyo)
Collaborative harvesters (digg, netscape, reddit, popurls)
Social Q and A sites (Yahoo® Answers, answerbag)
Social networking sites (mySpace, facebook)
Media sharing/community sites (YouTube, flickr)

In many regards social media optimization is analogous to classic public relations though largely targeted at and moderated by autocratic social communities.