I'm currently drafting a social media strategy for my company, laying out the business case and identifying how these tools support our objectives. Since my report audience is executives with limited exposure to social media, I've drafted working definitions to guide discussion. As usual, writing encourages mental discipline, so I've had to think hard about what "social media" and its kin, "social media marketing," really mean: It's not a technology, it's a strategy. It's not two-way conversation, it's multi-way. And it's not purely customer-centric, because the company's in the conversation, too.
Here are my current working definitions. Please tell me what you think:
Social media
A category of communications that let people create, share, and discuss materials online. Social media integrates technology with social interaction to let people construct meaning through shared stories and perspectives. Social media offerings range from internet pure-plays—social networks, photo and video sharing sites, or social bookmarking sites—to simple tools embedded on a traditional site allowing users to engage more deeply with its content. Fundamentally, social media is about multi-way conversation, not one-way broadcast.
Social media marketing
A category of internet marketing that leverages the power of social media to connect companies and customers. Social media marketing seeks to build awareness and shared understanding of a company’s brand and products through multi-way conversation between a company and its core audience. Social media marketing relies on viral, word-of-mouth strategies that let constituents create, distribute, and discuss content about a company’s offerings. In exchange, the company enjoys the benefits of increased exposure, real-time targeted market research, and enhanced customer affinity.
Update, June 24, 2009: See my revised definitions based on your feedback.

For Social Media, I would add (at beginning or end) something like: Think of it as an amplified and accelerated version of "word-of-mouth," with the added ability for anyone on the Internet to participate, or to later discover the conversation through search.
Might also provide an example of "simple tools embedded on a traditional site." As in, "such as comments."
For Social Media Marketing, I might add something like: Because of the Internet's ability to reach many people very quickly, and for people to later search or discover links to previous conversations, the impact of social media marketing can grow very quickly and last a very long time, for topics both positive and negative. [This would later hook to the idea that managing social media requires on-going engagement on a daily basis, not a "project" or "campaign" mindset.]
At the beginning I might also say, "...to connect companies and customers, and customers to each other."
I might also add a general proviso along the lines of: A defining characteristic of both Social Media and Social Media Marketing is that the conversational voice is friendly, as if you already knew the person you are speaking with, rather than a more "professional" tone designed to "communicate" with an "audience."
Re-skimming the Cluetrain Manifesto every few years is helpful for ideas; most of that stuff is still highly valid, despite the somewhat dated attitude.
Posted by: Michael J. | 28 May 2009 at 10:56 AM
Excellent points, Mike. Thank you! (And yes, the Cluetrain manifesto is staring at me from my desktop now, in all its fluorescent orange and gray glory.)
Posted by: Meg Houston Maker | 28 May 2009 at 11:00 AM