I am not sure about you, but when I first joined LinkedIn in 2003 I had a strict linking/friending policy. I would only link to people who I worked with… people who I could recommend with at least one story or professional experience to back up my opinion.
I did the same for Facebook in 2005. I would only become a friend of someone who I actually considered to be a friend outside of one context (professional, social, sports/athletics, school, etc.)
Same goes for Twitter in 2008. I would only friend someone whom I'd feel comfortable sharing any number of life's details — professional, social, etc. But then Twitter was used more and more for sharing interesting links, a combination of professional observations and the mundane details of life.
Something interesting happened along the way. The networks evolved. I got repeated friend requests from people who didn't *quite* fit my intended way of using each social network. I was put in the lose-lose position of either rejecting the request & risk offending them or accepting the request & diluting my intended use of social media. Not being eager to burn any bridges, I started accepting requests that didn't fall into the policy I had charted for myself.
And now all my social networks are a mess.
On LinkedIn, the slippery slope began with work contacts who I didn't interact with on a regular basis. Then I started adding work contacts who I didn't know well (just folks who worked at the same place at the same time). Then I started adding people I knew, but not in a professional context. Then I started adding a few fellow alums from schools I'd attended. Then finally I started adding people I actually didn't know at all. All because my lines blurred to the point that I couldn't justify rejecting a friend request on the off chance that it might come back to haunt me.
Facebook went exactly the same way. It started with close friends, then work contacts (many duplicated with LinkedIn), then other folks I knew, then other folks I used to know… and so on. I see similar things happening with Twitter now and I don't like it.
More and more, I hear stories of people pruning their friends lists. I think this is a great move and possibly indicative of what I'd term "Social Media 2.0"… the next evolution. People have talked ad nauseum about the importance of filtering through the nonsense/clutter and making social networks more useful in coming months/years. But I wonder if the first step isn't the widespread adoption of "friend policies". I have seen particularly famous people in our industry post on blogs or their LinkedIn pages about the rules they use to filter contacts. I can see us all employing something like that as our worlds collide more and more.
Right now, my LinkedIn contact list and my Facebook friend list is about 80% duplicated. This seriously needs to change, and it will. So if you're currently a friend of mine and you aren't in a few weeks, please don't be offended. Work is work. Play is play. I'm just trying to get better control of my worlds and I'd really like to keep them separate as much as I can. Occasionally, I'd like to communicate in a professional context with my professional contacts. I'd like to share pictures, stories, and good times with my close friends outside of work. My blended professional and social life isn't working for me, and I quite frankly can't and don't want to be on my toes all the time. 
I admire your attempt to make sense of it all. I’ve just sort of given up trying to find substantial value from social networks. I don’t put much on Facebook (I don’t trust them), and I can safely say I’ve never used Linkedin’s social features for any productive purpose.
Facebook has been reduced to an (admittedly helpful) glamorized rolodex, and Linkedin not much more than a pretty good online resume.
But then again, I’m an internet curmudgeon.
So I am going to disagree with you on this one. Here is my thinking behind it. I just went from 120 “friends” on Facebook to about 220 in a month. I had the same rules as you did about only wanting to allow people I knew or worked with. But here is where you and I differ. I am trying to build MY brand, the Donald Harris brand. And to do that I need to get my name in good standing with as many people as I possibly can, especially those I don’t know. I don’t think this is ever going to be a wide spread policy on cutting your list to only folks you know I see that as a huge step back to web 1.0 and keep things private and local. I say get your name out there and make NEW friends and contacts you never know where they may help in the future.
Donald Harris
twitter.com/tallgamer
I can’t let social networks be useful to me only as a professional/branding tool.
Pardon me for not walking the capitalist line here, but if corporate/business/marketing interests permeate social networks to a significantly greater degree, social networks will suck more. Like the NBA. Like MLB where the Cubs are trying to get a corporate sponsor for Wrigley Field. No thanks.
Can’t we use the various social networks to do all of the above? Why not use LinkedIn exclusively for trusted professional networking, Facebook exclusively for friend/family networking and Twitter/MySpace for branding/enterprising?
Like y’all, I’ve been through several rounds of pruning on Facebook and LinkedIn over the last year or so. I got tired of receiving LinkedIn Introduction requests from people I couldn’t really vouch for. I got embarrassed when professional peers saw Facebook pic uploads and wall posts from my *occasional* benders… I’m relatively new to Twitter but my plan is to completely let go and see where it takes me; I think Donald has a good point — we should use at least one of the networks as a branding/ enterprising tool and get the network as big as it can possibly be. I’m also delinking the twitter to facebook connection so I can keep facebook separate (thanks LT).
@TVG
I tried keeping things separate and to a degree my Linkedin is all professional contacts only. Facebook I wanted to be only for my actual real life buddies…. just turns out that all my real life buddies are industry leaders in gaming. And we always end up talking shop. I think if you are a good PR/Networker your contacts wont look at you as a professional contact but a friend.
I often feel exactly the same way (especially about keeping my LinkedIn “pure” — less so about Facebook).
I’m trying to get my 39-year old mind around the lack of privacy that the newer generations are leading us into. When we were young, “privacy” was earned and part of becoming an adult (e.g., getting your own room, opening your own mail, etc.). But that expectation of privacy — or perhaps the desire for privacy — is gone now.
So I’m going to let it ride and see what happens.
Privacy concerns are a big generational difference. We’re both old enough to remember the beginning of the consumer Web in 1995-1996… people were concerned about getting banking information and e-mail through a Web interface. Now folks think nothing of letting Google read all your mail, exposing your exact GPS location to the World, and Tweeting your every life detail. It’s insane but it’s the “Post Web 2.0” world.