A million downloads of a free app is not really that noteworthy. My friend made a simple, free iPhone game in a weekend where you tap on a soccer ball and keep it from dropping and routinely gets 10s of thousands of downloads a month with absolutely no marketing.
Your friend is a genius and might be the next pg.
1M downloads with 1M+ dollars in investment is not noteworthy. You can basically pay for that much downloads. Not to mention its a FREE app!
They got that through marketing, not technology. Have you seen the launch video for Summly?