Actually, lots of people here on HN have been inquiring about Trello's business model because they, presumptive consumers, are running businesses and don't want to use a service that's free today and might be gone tomorrow. The fact that Trello now offers a business plan increases the perception of stability.
So a guy has to blog about in answer to those "lots of people" asking? Or could he have just replied to them in the discussion of HN? I don't know - seems a bit self-serving and like an utter waste of time for me. I like/use {Services A, B, C...Z} as well but I don't need to blog about every one of them. I suppose his next post is something anti what this post is - something like, "Why I use Gmail and am not paying for it" or whatever. Meh.