What is a Social-Media Agency?

I graduated from college in 1996 and, shortly thereafter, went to work at an early interactive agency in New York. Netscape had come out the year before, and my colleagues were a ragtag group of Madison Avenue refugees, reformed academics and eager college grads like myself. We designed websites for big companies and tried to figure out how this new thing called the internet was going to work as a marketing tool.

Back then, my chief concern was that the established ad agencies were going wake up one day and realize that they had all the client relationships and that building websites wasn't rocket science and then they'd smoke us. Guess what? Never happened.
Why? I'd welcome other people's opinions here.
Here's a starter list:
Traditional agencies were in the process of distancing themselves from production work.
The web looked crummy. Ad agencies are about beautiful work that wins awards. Bad fit.
It kind of was rocket science: At least from the agencies' perspective. Tech was critical to success, and they were primarily creative organizations.

Let's fast forward to 2009 -- and to my question "What is a social-media agency?" First of all, only a small percentage of the large interactive firms from 2000 still exist. Those that do include Organic, Agency.com, Digitas and Razorfish. Some great ones, like Schematic, launched during the bust. In the intervening years, there's been a broad acknowledgment that the skills and value delivered by interactive agencies are different that those of the lead agency, and the two have learned to play together much better.

As Mark Twain once said, "History doesn't repeat itself, it rhymes." And boy is it ever rhyming now.
Again our markets have melted and are reconstituting in unpredictable ways. Again consumer behavior is evolving at a dizzying pace, accelerated by changes within the larger economy. Again the web is at the crux of this change. There are 3 things I'll call out here as significant:
The web has become social; 75% of U.S. adults have contact with social media, according to October 2008 data from Forrester.

Television viewership and periodical use is down, online consumption is up.
Users are making and consuming each others' content.
Clearly this is meaningful for brands and marketers. Assets from media they used to control (print, broadcast, online publishing) are migrating to ones they don't. Even worse, the new online party is invite only.

Clearly, the risks of not adapting to this shift are great as are the rewards for getting it right.
The reason I'm interested in this subject is because I am trying to build an agency that can serve as dedicated "social-media agency" for a brand. In doing so, I need to define what "social-media agency" means, what skill sets are required, what services we offer and and how we measure the value delivered. And what it costs.

In my next blog, I'll incorporate feedback from this one and begin to discuss:
Why I think brands need a dedicated social media agency.
How an effective social media implementation requires combining the skill sets of marketers, game designers, film makers and technologists.

What goals we're setting for our clients and how we measure them.
Why earned media is becoming more important than paid media.
In the meantime, I'd love to hear feedback as well as the names of other "social-media agencies."
~ ~ ~Reuben Steiger is CEO of Millions of Us.