[annekate]

Enough to get statistically significant data. There are programs to get $100 AdWords or FB Ads credit and that's more then enough to get a few thousand to 10k impressions on your ads and give you decent data about how well they perform. I would usually set a testing campaign to spend about $10/day for 5-7 days, and would shut it down early if it was looking particularly bad.

Our app is free, so we aren't eager to pay for installs at any price, and paid aq is not a major channel for us. The lion's share of our new users come from organic search, social sharing, and word of mouth.

[jqbx_jason]

Can I ask for a ballpark of what # of users it took to get to that inflection point when SEO and word of mouth takes over? At least in my experience getting to there has proven to be the main challenge.

Also- thanks for taking questions and congrats on your success :)

[annekate]

It entirely depends on the domain so there's no good answer for this.

Our growth has been remarkably steady, with minor seasonal factors. If the majority of your acquisition channels scale with the number of users (SEO, social, viral) then you should see a steady accumulation of momentum over time, even from a very small number — perhaps the low thousands.

We've had a strong word of mouth factor from the very beginning, but I attribute that mostly to the brand and the fact that this is an underserved market. Parents have traditionally been invisible to tech companies and they are delighted someone is finally building for them.