Entrecard is a good way of getting traffic to your site and a number of people already have the widget up on their blog and it has been working well for them. Credits can be obtained in a number of ways and some people have a stack of credits that they don’t know what to do with which they could use a virtual currency.
Some people have even gone as far as to sell credits. A question I have is how much credits are worth in real dollars? I bid a bit of research and found that at the end of last year, sitecash put up an auction on eBay! for 50 credits which ended with a winning bid of $1.25. Could this be indicative of how much they are worth in real dollars?