Assuming you'd need 1 million downloads to make $1 million, check back when WP has 20 million+ devices in use.
In Dec we heard the figure of 1.5 million devices sold to Carriers. A month later we hear that 2 million devices have been sold to carriers.
Not all of those devices were sold to customers, so we can't say they are running 500k activations/month, so lets take that down to say 300k activations/month after being on the market for 4 months. Assuming they sold 200k in the first month, that's 10% growth/month. A nice comfortable number.
If they are able to continue on that growth cycle it is 24 months to 20 million devices. However, with the explosive growth that Android saw, 300k handsets activated per day, I suspect we'd see WP7 reach 1/4 of that within the first year. So let's say at 16 months they are activating 2 million devices a month.
Either metric, you're looking at 1.5-2 years to reach 20 million devices.
Thoughts?