Lately I have been amazed about what kind of features social networking sites are adding. This includes things like, as I've mentioned before, showing what you have done on the web automatically to your friends. This assumes that your friends will be influenced by it and do the same, thus generating advertisement for the company and money on the social networking site's pocket.
But what I think people don't quite understand yet is that there are lots of types of social network connections, and each works differently. It's not sufficient for me to say "he is my friend". I have to say "he is my friend, but our relationship is only work-related. So that if I befriend somebody from work, I don't start to spam them with messages like "hey, I bought my new lizard!" or "I wished I could afford this new Mac laptop...". But it would be alright if they saw that I'm currently reading something like "Tapping into Unstructured Data: Integrating Unstructured Data and Textual Analytics into Business Intelligence", which most of my other friends wouldn't care about.
What is the consequence of it? Fundamentally: people get afraid of actually doing stuff online, because you don't know how people will interpret it. People get bored by the 90% of the things you do that aren't that interesting (and each person's 90% is different) and stop paying attention. The final conclusion is that the business just doesn't work very well any more.
Solution? If I was a semantic web guy, I would say: add semantics to your friendship connections. Then, by gathering semantics of your activities, you can create more powerful and robust "filters" to partition your life correctly.
But I'll pretend I'm not a semantic web guy and say: just let people choose. Create a few types of categories, like "professional", "personal", "family", "fan", "joe that I decided to accept in my network" and then allow mutual filtering (not only I can filter somebody out of some types of data, but somebody can choose to be filtered out of some type of data). Give people simple choices and help them choose. There is lots of money to be made in this business.