Danah Boyd has an excellent post on the differences between adults and adolescents when it comes to blogging and other forms of online expression. In her post designing for life stages Danah Boyd writes

Identity formation

When youth are coming into a sense of self, they move away from the home and look to the social world to build a socio-culturally situated identity. In other words, they engage in the public in order to make sense of social boundaries/norms and to develop a sense of self in relation to the broader social context. Youth go to the public to see and be seen and they negotiate a presentation of self depending on the reactions of peers and adults. Public performance is about getting those reactions in order to make sense of the world.

A main role of things like MySpace and Facebook is to produce a public sphere in order for youth to negotiate their peers and learn about the social world. People often ask me why teens don't just go out in a physical public. Simply put, they can't. We live in a culture of fear where most parents won't allow their children to go anywhere without supervision. Youth no longer have access to the streets or even neighborhood gathering spots. They are always in controlled locations where the norms are strictly dictated by adults - this is not a public sphere in which teens can make sense of sociability. Thus, they create their own. (Note: the production of a public and its implications is the cornerstone of my dissertation.)...

Contributive Participant in Society

And then we become adults. The bulk of adult-hood is evaluated based on contribution to society, participation, what you can create and do. It's about being a good citizen, laborer, parent. It's about the act of doing things. Your identity gets wrapped up in how you contribute to society ("So, what do you do?"). We ask youth about their hobbies and friends; we ask adults about their jobs and children. When we speak, we think that we have to produce information, be relevant, be efficient, be contributive. (And people wonder why growing up sucks.)

Nowhere is this shift more apparent than blogging land. While youth are doing identity production in terms of sociability, adults are creating new tasks for themselves - documenting, informing, conversing. It's all wrapped up in being part of the conversation, not in simply figuring out who you are.

This is one of the reasons why whenever I see words like blogosphere it makes me laugh. The worlds largest blogging site is probably MySpace. I suspect that MSN Spaces is the second largest although I'd have to ping folks from work to confirm. Both sites have significant populations of young adults (aka teenagers or adolescents). However whenever someone says blogosphere they usually mean some specific subset of blogs such as technology or politics focused blogs. Although A-list bloggers like Doc Searls, Dave Winer and Robert Scoble give the impression that blogging is about amateur punditry that competes with journalism and corporate blogging, the fact is that a large segment of the blogging population are just trying to express their identity and discover themselves online.

People building social software need to understand the needs of both classes of users. In fact, it's actually more complex than that because you often also have to factor in cultural differences as well since the Web is international. If you are interested in blogging and other aspects of social software, you really should subscribe to Danah's blog.