Mustafa Kural

@makis_spyratos1 thanks you for reply. Facebook is not so though for us as we can put the product in front of huge target audience with relatively small budget. The problem is the measured interest this way doesn't mean conversion (sales), so we plan to ask for more commitment with the from we present with FB lead ads than only asking for email but ask for couple of questions. If they answer...

It depends on what type of product to a degree. I would use Quora as you can laser target your audience. Facebook is also great due to sharp targeting possibilities both paid (ads) and free (groups). All the best