Hitting this goal took a lot longer than expected but I learned a lot from it. Just because you put something out there doesn't mean people will buy it. The majority of these subscribers were people I've been talking to for 2 years about my app/site and have supported me from the very beginning.
There are also a good number of people who are waiting for certain features that I've yet to complete. So my goal now is to get those done and then work on improving the experience for existing customers.