See AgileMethods. The idea behind NonIntrusiveMethods was methods that did not intrude on a programmers daily work. Instead it should support the programmer so that he/she would be able to deliver value to his/her customers. The idea came about because EirikMangseth was growing tired of noting that to use a method/methodology you (often) had to accept a big overhead and a lot of bureaucracy just to get going. The alternative wasn't much better either. So there had to be a better way and that way was coined NonIntrusiveMethods.
So should we just look at the pages AgileMethods and AgileProcesses, or is there something further to say here that is different than over there?
Don't think there's more to say at the moment. Added this page as part of the Agile-lore.