It's not a marketing blog actually; it's a developer blog by my team and I who work heavily and provide technical details on how we're doing interesting things with docker and swarm.
Literally nothing is written by "marketing" - just developers. And it's definitely not spam, if you look at https://getcarina.com/blog/push-button-lets-encrypt/ for example it's a complete tutorial on a simple nginix and docker let's encrypt post.
If it ever a marketing blog, I'll happily give myself a wedgie.
I hate to be the one to tell you this, but it's a marketing blog run by developers. Marketing isn't some specific department certified as containing Marketers by the federal government. It's an activity with a goal to expand the market reach for a product, service, brand, or any other entity.
This is marketing content... And there's nothing wrong with that! We all market ourselves every day of the year. We may not admit to it or realize it, but it's inescapable.