My company maintains a very popular blog on testing. It has helped us land mutliple clients. We get a few inbound enquiries every month - usually from really small startups and/or QA directors that are looking to quickly implement test automation. After my own personal network and past clients, my blog is the most reliable source of clients. The simplest post that resulted in a client was one we wrote on how to run a Selenium test on BrowserStack using Python. The most advanced post that generated a lead/inquiry (but I couldn't close) was one on testing a Natural Language Generator.
What we write: We mainly write to make a tester's life easier and interesting - so testing, automation, tech we use at our clients and the different tools we use to test. The one other rule of thumb is that if the engineer spent more than 2 hours Googling about a problem, they should write a post about it.
Background: I established the habit as soon as I had an employee on the bench. It took over a year and about 30 posts before we saw even a little (~1k pageviews a month) traffic. It was about 18-months of regular writing (~50 posts) before we got our first client through our blog.
Pros: The habit has been a good for both my employees as well as for my business. The posts are good references for new hires and easy to pass on to our clients too. My employees also credit writing blog posts with helping them think clearer and articulate their thoughts better. We also look smart when our clients Google for something and stumble into a solution one of our engineers wrote.
Cons: The start was a slog and demotivating. Writing is still hard and time-consuming. As we grow, it is harder to sell new employees on the habit. The articles we enjoy writing barely get any hits [1].
[1] I loved this piece of work that used color paper, an Arduino and a servo-motor to test the Fitbit heartrate monitor: https://qxf2.com/blog/testing-the-fitbit-heart-rate-monitori...