Marnie tells me that one of her takeaways from last week's Web 2.0 conference was the definition of Web 2.0 software or sites or applications as tools that become more valuable the more people use them. If so there may be a natural congruence between the community/nonprofit sector and the Web 2.0 software world: nonprofits have a lot of experience with how to nurture communities, and in many cases have established the scale and breadth of relationships that could provide an instant user base for a Web 2.0 tool or community.