A promise like this would be a good incentive to get into Nxt. Get coins, run the client, etc.
How will u counteract the Sybil attack? People should give something valuable in exchange for NXTs, without this ur idea will be sybil-attacked.
But only if you give away the coins for every account equally. Or I am missing something?
My idea is a simple giveaway, based on previous Mining Ratio (as seen in blockchan explorer). Right now most blocks have no fee, but the block being mined anyway. So why not give something to people who bought coins, and mined with it early on? It's a much more just, and motivating giveaway than a "post your address topic".
It's possible I'm overlooking something obvious, if so, please tell me.