I just read about this in an german speaking online magazine. Diaspora is the first non-commercial(open source based) approach of establishing an alternative social network, where the user opposite to other networks remains in full control over his(hers) data. People who know a little about data and the internet in general can probably imagine that this is in fact a quite hard task to archieve.
If I got it right this network promises something Facebook & Co will never be able to provide you with the biggest possible safety for all kinds of data you may want to share with a choosen number(by yourself) of people on the internet. Still I'm cautios, so when I registered myself I didn't use my real name, future may show how trustful diaspora is able to remain.
More infos on wikipedia here:
en.wikipedia.org/wiki/Diaspora_%28software%29
If you want to set up an account:
joindiaspora.com/
somat
