2) Don't have the mindset that if you don't get any traction in a few days, you're doomed. Doing this is a long, long road, a year.. 2 years minimum. Just keep plugging at it, and don't just try 1 thing. Don't just post in Ask HN and expect it to be enough. Pitch to bloggers, mention it in forums, mention it in real life, talk to journalists who wrote about similar ideas, keep writing articles for SEO, etc. Just keep doing all that, and be patient.
Go to Google Alerts, and set up an alert anytime a blogger talks about something that is relevant to your service. Then submit a comment, or email them telling them about your site, and see if they can review it.