If you go down the trading platform exchange route you need to be aware of legal implications right? There's a reason in the UK we still don't have a good exchange, although it would depend on format of trading platform.
I think a general ''what is DRK" site with affiliate links to...
With the current rise of Darkcoin it makes sense holding the domain as you would the cryptocurrency. More DRK is worth the more your domain will be worth... I'm also in the DRK domain real estate game :)