Yes I would totally build a channel before a product. That's what we did for our current product. Be a thought leader / expert in your space even before you have the product.

I think about this a lot, and encourage most people to go this way.  Some people are well positioned to do this, and it seems like a no brainer. At minimum if gives you a hot list of people that are good candidates for early adopters or customers.

How would you suggest you do this when when you have a strong horizontal knowledge, but less of a reputation in the vertical? Horizontal to me means that as a company you are doing the same thing for customers, but they could be in multiple domains.  And the vertical is the identity that prospects align themselves with. When you have horizontal knowledge, you know you can perform but don't always have the language or reputation to convince your ICP that you have the expertise.

Then you are faced with the question of how do you develop the vertical knowledge and expertise. You could a) "fake it till you make it" producing content then build,  b) build it and get a few success stories to lean on, c) hope and pray.

I 100% agree that founders need to do more community building to launch into. I can attest to the fact that I would eagerly consume education on how to do that in a genuine fashion with integrity.

I would say CAC isn't 0 with that model, it just precedes the building -- which may be safer, even if as @Jarek Ostrowski says it may be misleading.  But we always have to read between the lines on what prospects and customers want. I sold a 40k project for our platform before building anything. but I still question if I validated the idea correctly.

Lastly, building and audience and building a product could happen simultaneously -- though it may be a time splitting operation at the beginning, and individuals tend to only be able to do one thing well at a time. If you can build something to capture some proof, and create a fan for a success story, that seems worth doing as well.

@Ed KangMy Traction book is arriving today. Looking forward to digging in and marking it up. Also, I am happy to be your guinea pig on building a following at our current juncture.

It's nice to have an audience to get feedback from, but I wouldn't rely on them to come up with ideas or to come up with a product, or to even sustain that product long-term. There are countless celebrities with millions of followers who launch products that do nothing. And depending on the audience, it could actually be a detriment.

They might love you like family. And what happens when we tell family our ideas?

"Awesome idea!" or "That sounds cool!".

I think the audience you build over time will be more valuable than the one you started with.