http://moz.com/blog/holygrail-of-ecommerce-conversion-optimi...
This is exactly what I'm doing right now. Everything works as one big marketing funnel from tweets/pins/posts to free downloadable content and one-off landing pages, to single page apps, to e-books and videos, all the way up to SaaS. I have to come to love the term Amy uses for these: e-bombs. Finding customer pains and dropping e-bombs on them is a really lean way to learn a ton quickly, build an audience, and even make money.
If you get really good, you can make it into a repeatable process that works over and over regardless of your domain experience. That said, I still think it might be a little difficult for me to do this for, say, theoretical physicists. I'm personally inclined to partner up with domain experts rather than trying to do it all myself as a lone technologist.
Great examples in the post. Now let's see some more! I've seen Moz and 37signals mentioned. Who else are we missing?
EDIT: I realized that Deezer is not well-known in the US. It is a major music startup competing with the likes of Spotify and rdio in the rest of the world.
Makes you think, doesn't it? Maybe blogging was a little bit bigger than it was made out to be just a few short years ago.