What exactly would be a scam? where is the line that you would draw? Could you give a list of some eligibility criteria that needs to be met? I can understand obvious ones like AsiaCoin with hidden premine. I guess to a certain extent, hyping a feature and disappearing too. What about staying on and unable to deliver on promises? Instamining before the pools could set up the wallet? Premine? what's a non-scam percentage? Selling a percentage of premine to buyers before launch (IPO)?
Also, what's the workflow for exchange? How are you going to asses the value? Especially if they are delisted or like those 1 satoshi coins with no buyers and just sellers? Would you be maintaining a fixed rate for them based on the last sold price or something?
That is a fantastic question you ask there.
Where to draw the line? First starting, the community gets to vote the "scamcoin" they feel for being scammed.
In my opinion, premined coins where dev ran away with the money before releasing, IPO where dev took of with the coins, etc are valid scams.
Coins with only sellers but no buyers are just bad coins, no scams. As long as a coin is open, or has a dev team, it should not be considered as scam.
Scam is really where you invested money/hashrate, and the devs ran away with all money and never really delivered or supported the coin.
To exchange we first need to have a value for the ImScammedCoin. Therefore the other 50% will be PoW.
Miners will keep on mining and trading them, so the coin will have a value to compare to.
Then we can use fixed or variable rates for the exchange. Why not implent a voting system for the exchange rate inside the voting for the scamcoin for example?