P.S. I'm eager to talk about your use cases for the coming months. You can find my email on the website mentioned above.
I wish HN would do one day out of the month where commenters could post their "Show HN" that they released that month. Much like the Who's Hiring threads. It would help me find some awesome software that didn't quite make it to the front page.
The same idea for "Ask HN" would be neat too. A lot of subreddits have a weekly or monthly "Simple Questions" thread which are really helpful.
I don't have much use for it now, but I have worked in marketing heavy organizations in the past where I would have loved to have something like this.
If I could give you some advice though, it would be to really carefully figure out who you are selling this to and then target your website to that person. Right now, it seems to be mostly targeted to me. That's great, but to be honest, it's pretty trivial for me to set up my own database. And, when I set up my own, I don't have to worry about things like your backup policy, your privacy policy, where you and your servers are located, etc.
I think that you'd have more luck if you targeted it to marketing types. You get close to that in your blog (posting an HTML form with Captcha), but I'd love to see your conversions if you targeted the whole thing to non-technical marketers who work in technical fields.
I built my own version of this, API for a Google Sheet, but it never occurred to me that anyone else would want it!