From SAI:

The radio versus Internet thing is a bit surprising till you remember radio can play passively in the background in cars and offices. The Internet is something you have to actively seek.

Key point is not the technological capability of radio to be accessed in various environments — internet radio will soon be on equal footing, with ready access from the living room, mobile phone or car — but rather that its passive programming can be consumed while doing other things (driving, working, reading, exercising).

Internet radio will soon have the potential to be consumed during a greater % of a person’s waking hours than any other form of media; if the associated advertising is infrequent, relevant and compelling, internet radio’s economic potential is massive.