These days there is a large emphasis on social software. Their appeal is partly due to their viral nature, mass potential, and hype. I happened to stumble upon "a page":http://arnoldkling.com/econ/succfail.html that discussed social systems in terms of real world societies. Here's a list of seven failure factors listed on the page that indirectly hint at things to avoid on your own social software ventures.
* Restrictions on the free flow of information.
* The subjugation of women.
* Inability to accept responsibility for individual or collective failure.
* The extended family or clan as the basic unit of social organization.
* Domination by a restrictive religion.
* A low valuation of education.
* Low prestige assigned to work.