That said, there is something "social networky" that unites these otherwise-dissimilar "social networking" sites. The two features that seem to define the social network aspect of a product are:
- Some kind of page or profile for each user. The contents of this page vary wildly, but it always includes a name and often a picture.
- "Friend" links among the profile pages, which may or may not be bi-directional. These "friends" only sometimes correspond to real-life friends.
So what ARE the purposes of these many "social networking" products? (in random order)
- Enable people to send messages to their friends. This functionality basically defines email, which can be considered one of the earliest "social networks", though most email systems lack browsable profiles. Annoyingly, many other social networking products reimplement this function, with mixed results.
- Enable people to send messages to non-friends. There are two aspects to this feature: discovery (finding the people) and control (preventing unwanted messages). Email is weak on both aspects, and for many people, this is one of the most useful features of products such as Facebook and LinkedIn (I can easily find and contact people that I don't know).
- "Live" address/phone book. Sites like Facebook have fields for phone, email, etc, and since everyone maintains their own page, the information is generally up-to-date (vs the bad-old-world of everyone having to broadcast "please update your address books" every time they move).
- Less private communication. Email and IM are often too private. Life would be much less interesting if all of our conversations took place one-on-one in closed rooms. Part of what makes parties, offices, and other social environments interesting is that we can observe other people interacting, overhear conversations, and often join-in. Features such as the "wall" create a kind of public or semi-public email, allowing our friends to overhear conversations. Twitter is often used as a public IM/chat.
- Passive communication about my life. I don't want to interrupt or spam my friends every time I have some little bit of news, take some new pictures, or get a random thought, but I have no problem blogging or Twittering those things, or uploading to photo sharing sites (which all have social features now). Similarly, I enjoy seeing this information from my friends (but I wouldn't want them calling me on the phone to tell me about their lunch every day).
- Passive sharing of non-personal content. I'll occasionally see an interesting or amusing web page and want to share it with friends. I used to put these things into my IM status, but now I add them to my FriendFeed. Email, Twitter, Facebook, and Digg/Reddit are also sometimes used for this purpose (though obviously Digg is less "friend" oriented).
- Self expression. This is most prominent on MySpace, where user profiles are highly customizable and can have embedded music (which starts playing as soon as I visit the page). This behavior is very similar to decorating your house or bedroom in "real life" -- there seems to be some human instinct to define our identity through decorations, fashion, music, art, etc. Self expression is an element of all products which have browsable profiles, but on most sites identity is expressed more in terms of content (favorite movies on Facebook, job history on LinkedIn, tweets on Twitter, etc).
- Background information. If I meet someone new (or am about to meet them), I sometimes checkout their Facebook or LinkedIn pages to learn more about their background, see if we have common friends, etc. Obviously this also ties in with self-expression and identity in more social settings -- people "friend" each other after meeting and their MySpace page (or whatever) becomes part of that "first" impression.
- Dating. One of the earliest and still most popular uses of sites like MySpace, Facebook, Orkut, etc. It's less "explicit" than on dating sites, but by putting themselves online, people can see and be seen, plus get background info, see who their common friends are, etc. The Facebook newsfeed even tells us when friends break-up (or start dating).
- Jobs. Job hunting and hiring are essentially the "professional" analog of dating and seem to work in somewhat similar ways.
- Finding old friends. By enabling friend-of-friend and school class browsing, it's much easier to locate old friends, and therefore people do more of it. This also lets people track down old friends without appearing crazy (they can "bump" into them on classmates.com, or whatever -- no private detective needed).
- Keeping in touch with "unclose" friends (related to "passive communication about my life"). It's fun to know what's going on with people who we've known in the past, even if we aren't close friends. Profile browsing and newsfeeds make this easier. This can also make unclose friends into closer friends, as we may coincidentally be in the same city at the same time, be attending the same events, or just start chatting.
- "Micro-socializing" (I need a better term here). A lot of wall posts, poking, winking, commenting, Twittering, etc can go into the category. The comments on FriendFeed generally fall into this category as well -- someone shares a link or posts some photos, then they and their friends will end up chatting about it. This is somewhat analogous to the traditional "water-cooler" conversation.
- Word-of-mouth recommendations. Shared links, news, Yelp reviews, some Twitters, and the like provide us with information about what our friends are doing. Word-of-mouth can be very powerful since we typically trust our friends much more than random people. The new Facebook "Beacon" advertising system is trying to use this effect to sell things.
- General amusement for bored people. Clicking around on friends and friends-of-friends and even random people's pages can be kind of interesting. As sites provide more content (such as the links and videos on FriendFeed) or games (many popular Facebook apps are games) there will be even more of this.
- Publishing. This especially applies to blogs, twitter, flickr, and the like, but being able to subscribe to the content produced by our favorite authors and artists as well as friends and family is very powerful for both the producer and the consumer.
- Group sharing and socializing. This was traditionally done via mailing lists and that's the model behind Google/Yahoo Groups, but of course Facebook, Orkut and the like have have some basic group functionality too, and Ning seems to specialize in it by enabling each group to create their own social network.
This list is certainly not complete, but I'm way over my 30 minute limit... I look forward to seeing your suggested additions. I'll probably post an improved list at some point.
I also hope to explain how my company, FriendFeed, fits into all of this. It definitely has social aspects (the word "friend" is right in the name!), but it certainly isn't a social network in the style of MySpace or Facebook.