I don't know why Internet marketers who write things are so secretive. Most writers are secretive, too, but for different reasons.
Internet marketers and other people who are not professional writers (and don't want to be anything even remotely like a professional writer) have a tremendous fear that something they write will be stolen. I am currently ghostwriting a business project that the business participants (a) want widely disseminated, shared, and used but also (b) protected by an ironclad copyright.
Those two things don't go together except in the non-writerly mind. If you want your ideas shared, discussed, your templates and formulas used, if you want to change business practice with your ideas ... then you have to let them loose.
The other thing is that most non-writers fear that their ideas will be stolen. That's because they labor under the mistaken notion that good ideas are very scarce. Ideas are cheap. Once you understand a bit about the creative process and really get "in the zone," ideas come at you so fast and furious you can't keep up. There is no idea shortage.
Besides, you can't copyright an idea anyway. If you have an idea as to how you can eat whatever you want and lose weight, that idea is public. You can't own it. I can't own it. At most, we can develop something around that idea and then copyright the specific sequence of words (or images or whatever) that we came up with.
Let's say that I'm an evil writing genius (I'm not ... evil, that is) and I want to steal your article on the weight loss program that combines eating whatever you want with losing pounds and inches. Legally, I could get in trouble if the article is copyright and I try to put my name on it. But if I make enough changes to it, I can get my own copyright on it.
In other words, people can take your content, rewrite it, and copyright it themselves.
Which brings us to the other reason that the panic over copyrights is so funny to me. What do you think that the copyright is really worth? Most writers give away more material than they sell (there are reasons for this). While J.K. Rowlings might have some great content that made her rich, most of the rest of us writers just slog out material.
That's amateur writers. Internet marketers are secretive about ideas, mainly because they know that ideas can't be protected legally. The ironic thing about that is (a) ideas are plentiful and (b) two people will never develop the idea the same way. Coming back to the crazy diet plan, six different people could work on that idea and come up with totally different books, articles, or other products.
What makes content or writing so powerful is the personal spin. It's not the idea. And what's funny is that other people can't really steal your personal spin. True, they could possibly swipe an article here or there, but let's face it. Oprah is Oprah not because of any single show she did but because of her personal spin. Same with Martha Stewart, Donald Trump, or even the unfamous people who dominate specific niches and industries. It might be possible to swipe a recipe from Marthan or a quote from The Donald, but it's impossible to hijack their personal spin.
That's why writers and Internet marketers should not be so leery about talking about projects in development. If I told you I'm working on a new method of using keywords in your articles, you could grab that idea and run with it ... and maybe wind up in a totally different direction.
Nevertheless, sometimes we all feel like we'd jinx our projects by talking too much about them. A lot of cool-sounding writing projects die on the vine, so maybe it's better we don't shoot our mouth off. But steal ideas? I wonder if that's even possible!