I got involved in two threads on another forum that were both concerned with keyword density. There is a video from Matt Cutts which explains that Google does not have an "ideal" keyword density, (http://www.youtube.com/watch?v=Rk4qgQdp2UA) but even after the link to it was posted countless people continued to post different percentages of what they believed it should be. Unfortunately no-one seemed able to provide any support for these figures, and that is the reason for my starting this thread. What I would like to ask here is that if there is anyone on this forum who believes in and works with a set KD figure, are they able to give a source as to where it comes from? I have no problem with disbelieving what Google says, but I want some grounds for doing it. What I am specifically not asking for is either a definition of KD, or just to know what anyone thinks it is. I am only asking those who can give a reference to where their's comes from. If it is out there somewhere,I would like to see it please. My suspicion is that if it exists it is very old and that this is just one of those things that some people will not let go of, but I am ready to be convinced.