A comment made by Brian Solis at this week’s Media Relations Summit in New York triggered a walk down memory lane, or at least a flight over an island my avatar once visited.

Brian and his co-panelists were chatting about the current popularity of Twitter when he declared that the only completely worthless foray into social media thus far has been Second Life.

His slam on the Linden Lab virtual world stuck with me while full-time tweeters for jetBlue Airways, Southwest Airlines and Ford Motor Company received accolades for their stewardship of their respective brands.

Before joining Ford, Scott Monty worked with the self-described “social media insiders” that launched the agency Crayon by holding an event on the virtual island “Crayonville,” inside Second Life.

While Second Life and its currency of Linden dollars did not scale into a viable mass-marketing medium, it earned plenty of mass-media coverage and spawned experimentation that helped define a new career for people like Monty, jetBlue’s Morgan Johnston and Southwest’s Christi Day.

I was fortunate to work in a corporate environment with a long history of skunkworks projects.  PR Newswire EVP John Williams created an interactive T-button for press releases while most people were still using 9600-baud dial-up modems.  So flying around in Second Life in 2007 was not only  acceptable, but almost expected by PRN clients who were happy to see a partner willing to explore a world where avatar anarchists routinely trashed corporate buildings and disrupted attempts at commercialization.

What did PRN do in Second Life?  We gave away public toilets and changing rooms.  Of course, these rest rooms featured video display boards that carried the headlines of press releases originating from in-world businesses as well as out-of-world copy pertaining to social media.  We didn’t charge for distribution of releases inside Second Life, instead opting to collect donations for the Denver-based charity Water for People.  We also created the position of Ambassador to Second Life to build relationships with the owners of media properties and businesses in the community.

Needless to say, there wasn’t a sustainable business model for PR Newswire and most other companies inside Second Life.  But it was far from a failure on many levels.

Our “ambassador” picked up skills for one of the hottest customer service/PR/marketing jobs today — that of community manager within a social network like Twitter or Facebook.  A clean-water charity received a nice corporate donation.  Employees and select customers got the satisfaction of knowing PRN had dippped its toe in the water from an imaginary pixelated island to see if there was any business value.

In a way,  Solis, Crayon and other bleeding-edge marketers were also winners.  Sure, they were mocked for Coca Cola’s “virtual thirst” vending machines and Nissan’s attempt to give avatars Sentras to drive, but many of us were envious of their creativity and that they worked with clients who embraced new ideas.

I’m in awe of the tens of thousands of games and widgets that are now part of Apple’s App Store.

This touch-screen ecosystem doesn’t net big bucks for most developers. Many apps are free; most sell for under $10. But the fact that more than 10 million miniature applications – with quirky names like Midomi and ShoZu — have been downloaded thus far means that it can add up quickly.

The phenomenon is not limited to the consumer space. Salesforce.com has been encouraging developers to post their zany inventions in its AppExchange so there’s more stickiness with subscribers, some of whom might be tempted to leave for a cheaper software-as-a-service sales automation tool.

What has been less apparent, both in the B2C and B2B marketplaces, is a burgeoning service industry surrounding many of these large software innovations or online communities.

Just as Joseph Jaffe and his pals created the agency Crayon a few years back to monetize the frenzy around those setting up communities and businesses in Second Life, a number of PR pros and marketers are specializing in Twitter, LinkedIn and Facebook.

Few argue that experimentation and innovation are not vital to keeping brands relevant in today’s business world, so there is strong demand for a helping hand to prevent potentially highly visible online missteps.

The one category of service business we’ve seen and heard about the most is monitoring and gisting services. Corporations and agencies gladly pay services like Techrigy and Radian6 to learn what is being said about them and competitors online. (see Dan Schwabel’s list of players here.)

But monitoring alone does not give companies a voice in the conversation. That’s where England’s Twit4Hire.com, Australia’s Twitter Agency and similar outsourced service models pop up, along with Twitter practices inside traditional PR firms and ad agencies.

It remains to be seen whether this model will scale. Just as there are dangers of not being on Twitter, it is equally risky to task third parties with the upkeep of a brand – especially in an environment where authenticity and trust are such precious attributes.

Another service model that is flourishing, at least on Facebook, guarantees at least a million views of videos to audiences that can be targeted by age, gender and other demographics. Involver.com appears to be the Typhoid Mary of viral video.

While most of the world is in a recession, the stimulus package for risk-taking service providers is just a mouse click away.