"What is a clusternode? A clusternode is like a shared masternode, only better!
With a clusternode you will receive a reward when any one of the masternodes in the clusternode receives a reward.
Clusternodes don’t have seats, that's right, you can deposit as little as 0.1 of a coin and still receive rewards from that clusternode. This is possible using our patent pending Clusternode technology of bringing masternodes online and taking them offline. This also allows you to withdraw your funds at any time.
When you deposit coins into a clusternode, they will show up in your “Balance in queue” for that coin. Once enough coins have been deposited by the community, a new masternode will be added to the clusternode and your funds will be moved to the “Balance in cluster.” Once your coins have been moved to the “Balance in cluster” you will receive a percentage of each reward received by any one of the masternodes in the clusternode."
Interesting,
and only 0.005 BTC minimum to get listed through voting
https://www.mintnodes.com/https://www.mintnodes.com/coins/BBP