In this week's "economist" there was an interesting article about facebook and the limitations of social networks.
The article shortly discusses facebook's implementation of the social graph and how opening up the site to widgets developed by outside programmers and mini-feeds have been the 2 innovations key to it's present success. The most thought provoking however was the observation by Paul Saffo, a Silicon Valley forecaster that “The value of a social network is defined not only by who's on it, but by who's excluded”.
IWIW a Hungarian social network is probably an interesting example of what can go wrong when a platform turns into a hype. The platform has been a massive success in Hungary, but on the hight of it's exponential growing phase a lack of investment clogged up it's servers.
In May 2006 T-online bought IWIW for almost 4M EUR. Since then the platform has become much faster. Many users however will agree that the ever more intrusive advertisements and a never ending series of spam mail have turned the platform into a shadow of what it used to be in it's early days.