The previous five screencasts have been experimental. Anyone who knows Ruby on Rails can install the code and, since it is open source, anyone can make improvements to it. We have seen how the application programming interface (API) allowed for an independently developed killer app to be built. However, until today, to my knowledge, none of the new features shown in these "Stupid Currency Tricks" screencasts are actually enabled on real systems. Why? Because real people in real communities have not asked for them!
People who actually use technology for everyday needs often seem to be just fine with commoditized, everyday technology. So, today there is no OAuth, no QR codes, no Twitter, no Identi.ca, no Nokia n800. Instead, this screencast shows a feature requested by Kieran Sikdar which makes sure the right people are notified when a new request is created.
Since people can list what categories of service they provide and these categories can also be associated with new requests, we can limit email notifications to just those people whose categories match the categories associated with the new request.
Also, I should mention that if a category or sub-category doesn't already exist, anyone in the system can create a new one. The administrator of the system clearly does not have the specialized knowledge of the community for determining which categories of services should be defined.