Ask HN: DMCA, what defines: 'financial benefit'?

Source: http://en.wikipedia.org/wiki/Online_Copyright_Infringement_Liability_Limitation_Act#.C2.A7_512.28b.29_System_Caching_Safe_Harbor

Quote "Finally, where the OSP can control the infringing activity, the OSP must not derive any financial benefit through providing the link."

What on earth does this mean, No financial benefit? This is unbelievably wishy washy.

For me this is something important as while I'm not benefiting from people buying content (I stress that this is content will be creative, self-made, user uploaded content), however I will be selling accounts and online storage. Does this mean AWS/S3 is also unable to claim Safe Harbour?