This tells me that your real product is not free. You are selling a product, technology for making custom diagramming applications, that happens to have an offshoot that you can make freely available without compromising your core business model, and making it freely available has a better cost-benefit for you than trying to sell it as a cheap app, or for that matter not releasing it at all (releasing it gives you positive PR if nothing else). (Btw, is there a similar business model and explanation for hellosign? I assume there is. If not, the link you gave is not really relevant to this discussion.)
None of the above is communicated when you say "it's free!" on your front page with no other explanation, or when you ask "how long does it need to be provided for free before you trust that it will stay that way?". The critical factor is not how long you've been providing it for free; it's that the free "product" is not really the product, it's just a side effect of your real product.
If you really want to change people's attitudes about the issues involved here, find a catchy word that differentiates your business model from "free".
"Btw, is there a similar business model and explanation for hellosign? I assume there is. If not, the link you gave is not really relevant to this discussion."
Threads in topics often vary in subject. My posting would not be suitable as a reply to the OP, following from the top of this thread, I would say my replies are perfectly reasonable relative to the parent post.
I may have misunderstood your original post; I thought you were one of the developers of hellosign, who also happened to have a previous product that was marketed similarly. Looking at hellosign's About page and comparing it with the page you linked to, that does not appear to be the case.
I still think an answer to my question about hellosign's business model would be of interest for this thread, but obviously if you're not involved with hellosign you can't give that answer. Sorry for the misunderstanding on my part.
None of the above is communicated when you say "it's free!" on your front page with no other explanation, or when you ask "how long does it need to be provided for free before you trust that it will stay that way?". The critical factor is not how long you've been providing it for free; it's that the free "product" is not really the product, it's just a side effect of your real product.
If you really want to change people's attitudes about the issues involved here, find a catchy word that differentiates your business model from "free".