An excerpt from a contribution by John Willbanks:

“The standard that works best tends to be the least powerful solution to the problem, especially if it’s an openly released solution. This can be counterintuitive – why wouldn’t we want the most powerful one? – but it’s been proven again and again.

In technology, standards propagate like kudzu. Most of them go nowhere, representing an enormous sunk cost of time and money. And that’s because most of them are way too complex. The more powerful they are, the more brittle they are, the more expensive they are to implement, and the more they restrict the re-use of the system.

Tim Berners-Lee calls this the Rule of Least Power, and it’s one of the most important lessons I learned working at the W3C. There’s a simple reason for this – the more basic the markup of the content, the easier it is to write applications that process the content.

Thus TCP/IP, created simply to move bits between computers, begat a variety of new protocols like FTP, Gopher, Finger, many other protocols that layered atop the basic bits standard. Complexity from simplicity. Attempting to embed file transfer into the bits protocol would have made this whole process a lot harder.

And of course HTML/HTTP begat the entire Web, all the way to YouTube and Amazon and everything else. Writing video codes into HMTL wouldn’t have worked nearly as well as writing a standard that was simple enough to be extended by smart users coming along ten years later.

To the rule of least power we can add the rule of openness – the standards process should be as open as is feasible, and the standards themselves must be open. Users have to be able to read a standard, and to have the freedom to implement the standard, to be able to innovate atop it with new systems. “