I think a lot of people inside the field of SEO are trying to go broader so that if & when a particular search channel is a bit unreliable or unpredictable (loo

I think a lot of people inside the field of SEO are trying to go broader so that if & when a particular search channel is a bit unreliable or unpredictable (look at how many sites were torched in Google's Panda update) they can still keep the business afloat through other channels (paid search, social stuff, email marketing, and so on). I don't think you can ever really get rid of the fog in search completely though. If and when you disclose something publicly that reveals an algorithm weakness, ultimately what happens is people abuse the relevancy signal and then Google evolves their algorithm to place less weight on that relevancy signal. The other thing that happens is the cost of trying to influence that relevancy signal goes up. Some people have highlighted that in some instances domain names can be part of an SEO's strategy. Eventually that led to poker.org selling for a million Dollars! Over time relevancy signals that are shared ultimately either become more expensive to create, less trusted, or both. The other thing I would add is that you can know a good bit about what some of the signals are & it can still be a royal pain in the rear trying to create those signals. It is easy to write "build links" but search is a winner take most market & you can lose a lot of money marketing before you hit an inflection point. The same is true with brand building. And some brand building efforts are not entirely logical, but some are focused on exploiting the irrational parts of human nature. If irrational humans create the relevancy signals you need and irrational idealistic humans write the algorithms that grade those signals, then just rationally looking at the numbers does not guarantee you will be able to compete. You can be 100% right and still be plenty unprofitable in many business ventures.