One more question.
I see Pure POS on many coins yet, they have 1-4000 blocks POW.
How can it be pure POS if it has POW in the beginning?
That sounds similar to the system that Blackcoin uses.
If I remember correctly, those initial blocks are mined via proof of work in the same way Bitcoin is mined today. However, after a while, the coin disables PoW mining entirely and switches over to proof of stake. Hence there are two separate phases: a pure PoW phase and a pure PoS phase.
The PoW phase is there to distribute the coin. The problem of how to distribute a PoS coin is a tough one. Another option is to distribute them via an IPO where all of the coins that will ever exist are pre-generated all at once and sold in a massive auction. This method is popular but also somewhat controversial. Indeed this is the system that NXT, Qora, and a few other notable PoS coins have used.
So NXT and Qora have no annual interest and they have no POS block rewards?
The block rewards come from transaction fees in the network. Transactions are put into blocks which contain fees. Whoever forges that block gets the fees. The total number of coins in the entire network remains constant.
Which means no inflation...
Nice one!