Proof of Stake Velocity (or PoSV in short), is an original mining algorithm developed by Reddcoin development team as a substitute to the proof-of-work algorithm that was used at Reddcoin's inception. It is based on traditional proof-of-stake (PoS), but features modifications to the original PoS algorithm to promote more active network participation. It's name comes from the idea of Velocity of Money and alludes to the goal of PoSV to promote a better coin economy by increasing participation of coin holders.
In PoSV, Coin Age (a measure of how long a coin holder has held onto coins without spending or moving them) is not linear like in standard PoS algorithms.
By weighting Coin Age in this way, ReddCoin incentivizes token holders to regularly stake their coins and to maintain a cryptocurrency wallet online full-time.