There are lots of reasons to start and participate in a community mesh network. Open Source and Cooperative structures are something that we believe in since we participate in on this website and share our ideas and share and make other peoples ideas. I am sure a lot of this and working around shared resources as opposed to top down structures will be a recurring theme in this project.
The first reason I like the idea of off-grid community mesh networks is the idea of local servers with information and activities relevant to the people in each node. It also provides a more reliable network in the event of natural disaster or other calamity. This can ensure a robust communications network is in place for emergency personnel. I think that this can also provide a manner to provide localized real time emergency warning systems as well.
Second, it is a good way for neighbors to cooperatively pay for and share internet access. This can do a lot in the way of making access more ubiquitous through all sectors of the community and not just those that can afford personal internet service. This can go a long ways to improving scores in school, lowering crime, and helping to provide the adequate educational resources for people to thrive in a community as opposed to being left further and further behind.
Finally, I it can create opportunities for education specific to IT as the kids in the neighborhoods are probably going to be keeping everything up and running. If it the community is invested in the structure then they will be more invested in each other. They can band together and make better political choices that are relevant to there own needs.
There hundreds of communities in the US that have invested in Fiber with internet speeds that can reach as much as 100 GB/s. They are not being used because local politicians quietly sign into non-competition agreements with corporate behemoths such as Verizon, Comcast, and Time-Warner. These agreements state that the cities can't sell internet to residents and they can not lease or sell the fiber network to small companies to provide competition to the large providers. This is probably the biggest reason why I want to make this available in my area and available so that others can make significant changes with technology in their communities.