Depending on what you're starting, those are often the worst sort of people to target when you're starting a business. They're great if you're launching a customer oriented business that wants "everyone" as a customer, but most startups aren't that. Consequently they're not interested in what you're doing; they're just people who want to discover the latest thing regardless of what it is. Betalist, ProductHunt, etc are full of those people. They're easy to find. Unfortunately spending time courting them will give you the bad feedback (they want to please you rather than being honest), they'll rarely go on to become customers or evangelists because they're probably not your target market so they'll get bored quickly, and the whole process is a waste of energy.
I realise that sounds exceptionally negative, but this is an important thing for startups to learn.
On the other hand, if your service was something where I could pay you $2k after you've found me 100 paying customers who stay with my startup for, say, a year then you'd be selling something really interesting.