I decided then that organic search traffic is the way to go, but for that I need at least some links. My naive assumption was that highly-customized posting in appropriate niche forums was the way to go. I figured that since I am "adding value to the Internet" by making something free and useful, it would be well-received.
I was wrong. In most places, I see cold responses about "self-promotion/advertisement", and moderators delete messages in the blink of an eye. Even in places with "nofollow" links. I understand the frustration with ads, but (1) I am very careful to post in highly relevant places (2) I am convinced the tool is unique on the Internet right now - it's not like "yet another advertisement for X", and (3) it's free and its status as a "barely commercial" project is readily apparent.
I could try tricks such as pretending to be unrelated to what I'm posting ("Oh, look at this cool tool I found"), but this feels dirty. I always disclose my affiliation - seems I'm being penalized for honesty.
So, question: What are good, legitimate ways to let people know about a new, free, genuinely unique, genuinely useful, niche tool, keeping in mind that I can probably devote at most a day or two to promoting it?
Not just asking for this tool: I have many other ideas and would like to make them a reality, but there's no point in making them if there's no way of making the target audience even aware of their existence. Any thoughts would be greatly appreciated!