I blogged for months pre-launch with very few readers. It felt ridiculous to put so much into something that wasn't directly related to the brand I was building and was taking away from my sw dev time.
But when I launched, a surprising number of key industry folks read a significant amt. of the blog when they went to check out my site. Most didn't know me prior to my launch announcement, but after reading the blog they were convinced of my expertise in the area and a few have been working overtime to open doors for me. Likewise, a number of new users got to know me through the blog and came to champion the site after personally connecting w/ me & my background in the field through my writing.
It turned out to have been the best marketing / biz dev dollars I never spent.
I got advice many years ago from a VC that you should proclaim yourself the expert in whatever field you are entering. It turns out that the blog permitted me to do that successfully in a very low-key way.