The massive growth of fairtrade and other ethical living/marketing and corporate social responsibility demonstrates that there is a market for a recognised top level domain where people know there time online is well spent.
The demand and need for such a domain can only grow as global problems converge in the coming years.
In answer to the comment below about whether people care enough, the answer lies in building a credible destination which people trust. This proposal for an ethical top level domain is a simple idea but of course the structure is not a simple linear model of placing funds in an ethical pot for each click. Rather, it’s about involving users emotionally, socially and economically based upon trust.
Marek Kohn has written a book on building trust entitled ‘Trust: Self-Interest and the Common Good’. He argues that to build trust there needs to be give and take – a transaction or some other kind of engagement with a positive outcome which instils trust in those involved. If such an engagement with users is built into the domain’s system, then people will care and visit the websites within the domain.
It’s similar to fairtrade/ethically labelled products on the supermarket shelves. It’s about creating choice and empowering consumers and producers. Given the choice I don’t always buy fairtrade, but I normally do. Fairtrade growth has outstripped other retail sectors and signs are that it will continue to do so. There is also growth of ethical online stores but they are dispersed and difficult to find. A top level domain could tie them together and entice other online stores and services to join the commitment to our future.

I would like to put forward four simple arguments for a new TLD for "social enterprise" websites.
1) It would flag that this class of organisations exists.
2) The TLD may give a degree of assurance that this really is a social enterprise.
3) It could be used to organise a diffuse cluster of organisations around a coherent positioning.
4)The sale of domains could be used to raise funds.
Leaving aside questions of control and administration (which are, in themselves, not trivial matters), these are some issues to address:
1a) This requires a definition of what a social enterprise is that is clear and internationally-accepted.
1b) There would have to be a mechanism to tell people what the TLD means.
2a) To achieve this, some body would need to provide screening of applicants, against agreed criteria.
2b) How many people would really be interested?
3a) Postioning social enterprises coherently requires strong agreement on what that positioning should be.
3b) The mechanism to provide this branding and communication would require fundung and organisation.
4a) For an agreement to be reached to on how to use the funds, a significant number number and diversity of people and organisations would need to be consulted.
4b) For the funds raised to be significant, this TLD would need to charge a premium, get the agreement of resellers to pass this premium back to a specially-constituted body, and provide transparent accountability.
This may be possible, but it is unlikely to be quck, and will certainly run into contention.
I hope this starts you thinking and raises practical issues for solution.