Another great post from Eric Seufert discusses the merits - or rather lack of merit - in chasing top 10 positions in the app download chart. It's an argument that seems obvious: you should not spend any more on acquisition than you can reasonably expect to recoup from those acquired customers in revenue. Like I say, that sounds like simple sanity to me, but obviously sanity is in short supply these days.
Two other things strike me. Firstly - based on this evidence, which is admittedly limited, you cannot assume you'll receive a signficant benefit from chart-hacking in terms of a longer-term lift in downloads. All three examples departed from the top 10 quickly, which suggests that the flood of 'organic' downloads that supposedly accompany a chart position may not materialize - and certainly not if the chart position is down to decidedly non-organic means in the first place.
Second, the need to have a clear strategy around monetization. Eric points this out, and he's right. Having people using your app is one thing, but it is what we might call a 'necessary but not sufficient' criterion. It's essential to have a plan to turn installs into revenue, even is that isn't done directly through in-app purchases. If you don't have that in place, your position in a download chart is simply an extremely expensive form of vanity…