Don't worry, we do intend to share the data publically once it's all in.
will you post all of the data (in its original, unadulterated form) collected for free, unrestricted download by anyone for any purpose, including competing with last.fm?
intending to share, and actually making a public promise to do so, are quite different things.
No-one even knows if it's possible to crowdsource good enough BPM data like this yet, so even demonstrating that it's feasible would be progress :-)