Ever wondered how much overlap there is between your social networks or contact groups?

I always find it amazing that when I hit the “find people to follow or find your friends on X” button and add my email address such a relatively small number of users comes up.  Yet with fairly healthy numbers on each of the services I use, why is there so little overlap between the services?

Having received lots of “follows” on Twitter recently from friends on other networks, I started to examine how and why I use each service.

Here’s what I discovered (apart from the fact I need to pay a babysitter and get out more often and have a MASSIVE sort out to get all my contacts in one place at some point, perhaps when my daughter leaves home):

1. I am currently active in several email or social network apps/services (such as FriendFeed, Delicious, Twitter, LinkedIn, Gmail, Flickr, Facebook, MySpace, Huddle, wordpress, Yammer, Photobucket, Google Reader, Technorati, Slideshare, MS outlook)
2. Email aside, I began using many of these services in 2004/2005 – the oldest are MS Outlook, Photobucket and GMAIL and the newest is FriendFeed.
3. When I compare the friends I have on each service, only approx. 15-20% are shared across social networks, the remainder is distinct to an individual network.
4. Only approx. 40% of my social network friends are represented in my email contacts.
5. The exception is FriendFeed that has no distinct friends – all are shared with other networks.
6. Facebook has the highest amount of family and close personal friends.
7. LinkedIn has the highest percentage of colleagues and ex-colleagues and the highest percentage of overlap with my email contact book.
8. Twitter has the highest percentage of people I have never met IRL but feeds into the largest number of other apps (blog, email, IM, delicious for example)
9. The order in which I tend to use to strike up meetings IRL are Facebook/Facebook messaging or Twitter/Twitter DM->Email ->IM-> RL -> Phone
10. I use Twitter DM almost as often as email/phone to set up / confirm RL meetings nowadays (work related, not personal).
11. Connecting with people you don’t know varies in both etiquette and ease.  The easiest network to contact or connect with people on are Twitter, FriendFeed and blog networks.  I find LinkedIn slightly less easy in terms of approaching people you don’t already know.  For me the big no-no is Facebook in terms of approaching strangers you’d like to contact – I feel it is a personal network and I don’t accept invites there from people I don’t know and wouldn’t expect others to either.
12. With IM,email and mobile numbers, my rule of thumb is if you put them on your blog, it is fine to use them…providing it is relevant.
13. Very few of mky closest friends and family are on Twitter but the majority are on Facebook
14. In terms of the monetary value/benefits outside of the community and conversation loveliness of these services:-

• I’ve found work via LinkedIn
• I’ve saved recruitment costs by using LinkedIn and twitter
• I’ve been approached for new business leads via Twitter
• I’ve had press coverage because of the blog
• As a remote worker, Huddle saves me money on conference /long distance calls as does IM
• Email is by far the biggest time (and therefore money) drain

How do you do social?