The mainstream effect describes a level of popularity that a given technique may gain, which causes the general knowledge of it to become dangerously superficial.
When it exists in a small niche, amongst a dedicated community of practitioners, the technique proves to be highly effective. The technique is passed on from person to person in great detail and a deep understanding of the principles behind the technique are well known. As the technique gains traction, it is passed on faster and faster – and in much less detail. The result is that in many cases, only the name of the technique survives in common implementations. The mainstream version of the technique as practiced en masse is unrecognisable to the original community of practitioners.
Please get in touch if you have other notable examples and I’ll include the best ones.
Thanks to Mark Jones for the TDD suggestion.