Chris graces us with one of his extremely thoughtful pieces regarding the fabric of social networking/software: Dunbar Triage: Too Many Connections. This time he looks at the issue of maintaining relationships across multiple social networks and systems, especially in light of Dunbar's theory that 150 is the upper limit of efficient social networks. Chris offers shares views as to how such networks can be maintained, and filtered.
Because social media (which I loosely define as covering social networking, all forms of personal publications, syndication and aggregation) is my primary interest and focus, I have tried most services available. As I have blogged many times in the past, LinkedIn is the service that I have chosen to host my business network. I would say that at least 90% of the 600+ people I am connected to I have met in person, in a business or casual setting. The remaining 10% (or even less maybe) were added to my network before I implemented the rule Ross Mayfield taught me (by turning down my initial LinkedIn invitation) that social capital should be used essentially with connections from the "real" world, or with people who have been highly recommended by my "trusted inner circle".
These "unknown" connections are only problematic when they are part of a forward/connection request, and, by virtue of the lack of a shared context, I can't make any representation when passing onto the next person in the chain.
As to the maintenance of the network, and how often one needs to get in touch with each individual, it is a matter of one's purpose for networking - or using a networking tool. As far as LinkedIn is concerned, the two most useful features are 1) finding out how I can access a given person or a company, and 2) identifying people matching a certain profile (like a last minute speaker for our conference). And it has also become an interesting source of business or investment leads, because I have made the choice of providing quite a bit of information in my Linked profile, and very often referring to it as my main bio.
The VC/startup industry is revolving around efficient networking, and I have always found that what mattered was to properly meet someone (doing the breakfast, lunch, coffee "thing") in order to introduce your fund/startup/practice, and then it was OK to do business without connecting in person for a couple of years. And there are enough (daily) schmoozing opportunities (VC functions, industry meetings, social events, conferences) to get caught up. That is, if you care attending them.
Because of the way I use LinkedIn, as an online proxy of my rolodex, I don't really need to apply one of the 3 management methods Chris is referring to. Quite the contrary, the larger my trusted network is, the more visibility I can have on ways to reach a given person/company - potentially having multiple paths to reach someone, and choosing the most relevant person in a given context.