Wrong way round.
You want to know if clicks on illegal sources have an effect on legal sources.
Not if clicks on legal sources have an effect on illegal sources.
Yes, it's important.
No, they're not the same.
You want to know if clicks on illegal sources have an effect on legal sources.
Not if clicks on legal sources have an effect on illegal sources.
Yes, it's important.
No, they're not the same.
When? Where? To my knowledge, no such study or data in favor of that thesis exist. For music I know of a counter-study to such statements: http://www.scribd.com/doc/131005609/JRC79605, which concludes with
According to our results, a 10% increase inclicks on legal streaming websites lead to up to a 0.7% increase in clicks on legal digital purchases websites
and
Essentially these papers show that illegal music downloads have little or no effect on legal digital sales.