My bias is to “narrowcast” in the beginning. Choose websites, forums, newsgroups that are tightly focused on your target market. You attract less competition, your message cost is normally cheaper per prospect, and you often learn faster by taking part in the conversations in a focused community.
It’s not so much about being stealthy as sending a message to a tightly focused audience.
And, let’s face it, you know the least about how to talk about customer problems/needs in the beginning. Broadcasting your weakest message widely does you little good.
See also “Find Early Customers in Forums“
Trackback from your site.