It seems like getting the first 10k active users is the hardest for an app.
It seems to me that once you get over that hurdle you can focus on more iterative and compounded growth.
My experience with SEO and the app stores is that you need to really carve out a strong niche but then it's kind of downhill.
For example, my experience is that unless you have a large number of users the app stores sort of ignore your app.
Does anyone else feel like this?