I'm always surprised at how much push-back this one gets. The point I was trying to make here is that you DON'T need to be someone who spends every free moment blogging, writing open source code and so on. Stick up a few posts somewhere and leave them there, as a tiny piece of extra evidence that you're someone who knows how to do things. Maybe part of the problem is that I'm grossly under-estimating the amount of wo…
Here are the struggles I've had with this over my career:
* Public vs private persona. I'm a pretty open person and happy to share with people I know or where it feels "safe" (eg, Facebook where I more explicitly control the audience) but I'm deeply uncomfortable with publicly announcing things under my name on the internet to go god-knows-where. This is one reason I've been tremendously uncomfortable with Twitter. I absolutely despise the public-broadcast model, and I'm somewhat suspicious of people who want to make such a show of themselves (to build an "audience"). I've toyed with various forms of pseudonymity but that brings its own problems; I think it encourages antisocial behaviors and then at some people you have to 'expose' yourself (eg, when you have to tell your prospective employer, yes, NSAhacker31337 is my github, take a look!)
* Along with the above, blogging/demonstrating things always has a bit of a show-off feel. "Look at this great thing I know how to do, I bet you don't know how to do it!" Or, worse, you're demonstrating something "everybody knows" and you look like a naive fool.
* Consistency. I've made various "I should start a blog" efforts over the years, and inevitably get bored of the tools and want it somewhere else, or I don't like the tone I used to use, or I forget which site I used, or whatever. It's sort of like how "just go to the gym 3 days a week" shouldn't be that hard, but for 99% of people is.
Again, these are just my personal struggles, to maybe help you understand why people don't. It's nothing against your advice, which I think is fantastic.