I have tried to send several e-mails to opt in people and really never got a return on the investment. It is kind of like sending out your resume. It feels good but with out a network it does not do much. Here is what I have found helps get people to your site:
1. Build back Links from a variety of forums blogs news releases ect.
2. Contact people who have newsletters going out to people that might like your products.
3. Make sure you get submitted to as many sites as possible.
Be patient, it should take a business 19-24 months to get any kind of respectable following.
Peace.