I have 35 friends on Orkut and I know them offline also. It is useful to me because I prefer not to venture into MySpace or Facebook (I tried though!)

1) Marketing tool. The more connections one has, I think the reasoning is that the more potential eyes one might grab. I don't believe this philosophy, as they folks genuinely seem like spammers with little value to contribute.
2) Pissing contest. Ye with the smallest penis has the most "friends" on an online social network. ;) Somehow it feeds one's ego, regardless of one's true success.

I don't use either of those sites to keep up with my friends though. I use Facebook for that and my number is much smaller there, I think around 500 maybe if that. I guess what I am saying is it depends on how you are using this sites.

You can choose a Twitter client like Twirl which delivers every @yourname message to you, but the beauty of the service is that you don't have to. There are about 40 people following me that I don't know and don't follow... and I don't feel any poorer for having missed the occasional @ message.

I limited the number of people you can have in a crowd to 150 on crowdstatus.

There is definitely an ego thing at play as to who can aggregate the most LinkedIn, F'book, Twitter followers, etc. I guess it all depends on what your goals are online. If you are really trying to network and reach a specific goal, your example of 100-150 people is probably both manageable and effective at facilitating that goal. But some people want to follow Scoble or Owyang or Calcanis because they like the content they offer.

Sidebar: about two years ago, the Daily Show did a hilarious piece about this very thing. Trendspotter Demetri did this whole bit about all his MySpace "friends." Typical spot on Daily Show blast.

Facebook for dummies mentioned that it is a way to keep in contact with friends and family regardless of changes in address, telephone numbers, email addresses, or career changes. Facebook is kind or an Outlook (or other MS hater contacts manager :-) that keeps notifying you of your friends status, location, and updated contacts.

So what usually ends up happening is you have a large group of 'friends' who's only point is to show that you have a large network, when in all reality, your contact is limited to that 150 person limit.

I did a major facebook cull when I realized that half of the people I had on my contact list were people I would never talk to again, and in all reality, didnt want the hassle of giving them the 'limited' profile treatment. Its much easier just to delete.

I think on the web right now, more contacts is better, but as we adopt more and more services, decluttering social networks will become the most important aspect, not how many people we have. It just takes too much time.

Even with lifestreaming services, I dont have time to hear information from everyone I have ever met.

These services are at their best when you can utilize large ratio of the data coming at you.

I wonder what percentage of usefull/applicable information flows through my newsfeed?

Now to come to the real issue, how many contacts are too many contacts : my take is that outside marketing/opinion-sensing/self-selling it's really useless to track what any and every people you met does - what I would call passive tracking eg. through FriendFeed.

However, I do believe in what I would call active tracking eg. catching up with people you are likely/willing to meet at the next conference. You could add blogs and such in this dimension : you wouldn't subscribe to everyone's blog/comments but to blogs that consistently develop information that is valuable to you (such as this one).

Overall, the added information that you get by monitoring the say's-and-do's of hundreds of people online seems to me, and hopefully to anyone outside Bubbleland, of very little value given the time and energy spent on it; and in any case, of far less value than what you can get from a few real-world discussions with people you know and who know you enough to deliver the information you need, without the noise, and with the customized advice.

Do you follow him? http://i26.tinypic.com/21o30r7.jpg

Dunbar himself postulates man has developed language to overcome that 150 limit, and also notes that more complex societies such as ours are not in survival mode and do not seem to have this upper limit for group size.

Simply put, cities, nations etc wouldn't otherwise be possible.

The experience that we have a natural point of equilibrium to handle the cognitive overhead of maintaining social relationships isn't proof in point to me. Because I find I can easily maintain that equilibrium in multiple contexts: 150 people at work, 150 in my neighbourhood, 150 at my old employer, 150 at my old sportsclub etc., 150 writers who's books you've read, 150 in my old village, 150 in my old fraternity, 150 in my blog network. We switch between comfortably sized contexts all the time without noticing.

The primary aspect of mankind to me is that we have been delegating cognitive overhead to our environment, to break the barriers of our mind, ever since we started painting cave ceilings and putting marks in tree bark.

Facebook, Twitter, LinkedIn, are all just another cave who's ceiling you're painting. 150 has nothing to do with it, I think.

1) Social sites have changed social norms. A friend in the "real-world" is different then a friend on Facebook and different still from someone you follow on Twitter.

2) What is important is that today it is efficient to maintain loose social connections - whatever you call those. Now what can be done to benefit from maintaing loose social connections? http://tinyurl.com/5w4lzk