Communities around the world face problems, whether it's a lack of clean water or finding affordable and sustainable ways to heat and cool their homes. Using appropriate technology to solve such problems means taking each community's unique situation into account when devising a solution.
Why is this important?
Looking into a community from the outside, it may seem obvious what the problems are and how to solve them. Many well-meaning groups put a great deal of time, effort, and money into projects that they think will benefit a community. But, unless the people of that community have been an active part in defining the problem and designing the solution, the result can end up missing the mark and frustrating everyone involved.
Appropriate technology, on the other hand, deals with the issues that most concern a community, and does so in a way that is consistent with local culture, economics, and politics. For a project to be successful, community members must be collaborators, not just recipients.
Besides helping to make a project successful, community involvement also gives people a stake in the outcome. Instead of passively receiving assistance, people become actively committed to not only seeing the project succeed, but in maintaining its benefits into the future. In this way, appropriate technology is sustainable - designed with the community in mind, with their input, ideally with local materials, and in a way that is easy to understand, operate, and repair.
It takes time and patience to get to know a community and what it needs. People in the community also need time to establish a level of trust with an outside group, no matter how wonderful their intentions are. Once such trust is established, there is a much better chance that the technology will actually be used by the members of the community.
Appropriate technology is much more than nuts and bolts - it's also people, relationships, cooperation, and trust.