This probably already exists or wont work. Here goes:
If reddit or someone sponsored a digital currency, put money backing it (a small amount at first to discourage immediate redemption, 500 bucks for XXXX number of issued coins) and gave it to top commenters who could place the currency in circulation by giving special coin Rep points to users whos comments or links they like, maybe the market could grow, the value of each coin taking on more value as users gain more thru good posts or cool links. Giving a coin or receiving one would do stuff like increase the prominence of your comments you make or something.
The value is based on status at first more than redeemable cash/products and the monetary value could maybe grow thru the fact you could exchange them for products (reddit tshirts, etc) if you get enough. It might encourage traffic and people signing up to comment which would then increase ad revenue (perhaps you could gain coins for spending certain time on sponsored links or ads) a portion of which could go in a central bank backing the currency.
Bueller?
http://www.theonion.com/articles/best-most-original-idea-mans-ever-had-returns-1140,35025/
