The story of the Suri in Ethiopia and the introduction of guns reminded me of the introduction of the milktank in the Netherlands, which made a lot of impression on me when I read about it during my studies. Milk used to be collected in milkcontainers, which farmers put by the road side. But when the milktank was introduced (around 1975), the factories stopped to collect the milkcontainers and farmers had to use a milktank on their farms. The farms which had about 5 milkcows and practised mixed farming were forced to specialize: either invest in a milktank and specialize in milkproduction or specialize in agricultural production (wheat, sugarbeets, etc).
An example of how a technological change (the invention of the milktank) can influence practice (need to specialise and scale up milk production to cover the milktank investment). So choices in technologies to support communities of practice may also influence and drive the communications of that community (and culture of the community?)