In 2006, Martin Fowler posted his now famous essay on Continuous Integration. Looking back, what seemed revolutionary, radical or just plain crazy is now common, pedestrian and "just what you do." I love it.
Back then, building and releasing software was a real pain. Integration was something you did at the end, after code complete, and we didn't know how long it would take. Some people may recall how we, as an industry, spent a massive amount of time integrating code from one team with another, or even just between developers that sat next to each other. The arguments against it at the time seemed valid and impactful. Now they seem weak and silly.
Fowler proposed Continuous Integration, an idea that was simple, elegant and had far-reaching repercussions. By producing constant, automated, self-testing builds in development, a huge amount of resource overhead typically incurred down the line was eliminated.