David Allen's contribution to global productivity isn't as much his manifesto Getting Things Done as the extended conversation GTD created.
GTD got us all talking about productivity in a new way. Thousands (if not tens of thousands) of blog posts picked the system apart, offered variations on it, suggested better alternatives for different professions and personality types. People claimed they were GTDing or not GTDing and had very strong opinions about it. People built apps to support it, built apps to support the next best thing that turned GTD on its head, built apps that echoed core tenets of the system.
Anyone writing, reading, or even thinking about productivity today is living that experience in a post-GTD world where ideas like ubiquitous capture and next actions are completely embedded in the language and discourse of productivity. #gettingthingdone #gtd #productivity