I've validated a solution, have a few committed customers, and want to move forward with development and subsequent marketing of my app. In validating the solution, I simply went onto the yellow pages (YP.com) and got email addresses of local businesses from which I sent an email simply asking if they had the problem, not pitching a solution. This resulted in a very good reply-rate, which I was then able to begin a direct conversation and turn it into commitments.
Now that I want to broaden my scope of marketing, I'm considering the same approach, but don't want to wind up spamming people. I could begin email folks using the same approach, but this seems a bit time consuming especially if we are talking 1000s (but may be necessary) as I'd much rather write a solid email that gets right to the point.
Adwords is of little value as my customers aren't actively seeking a solution online, but once they are made aware of mine, then its been well received.
Any advice on what to do next/best way to approach this is greatly appreciated!