As a pay-for-service approach, it seems reasonable: you say you need some data, the appropriate people come up with it in the format you want, and you pay and get the data. But the Amazon-like angle seems odder to me: How will each of the bits of structured information manage to be sold more than once? Since most isn't copyrightable, anyone can buy a copy and then put it up online for free. I could go buy that Wal-Mart Store Locations data set for $30 right now, and publish it on my blog. Are you hoping EULAs will be enough to prevent this, or just that in practice it won't happen enough to matter, or people won't notice that the data is free online and continue buying it anyway?