Thrones are supernodes wich support the Crown network. They have several uses:

1. They allow you to make money when users set them up (40pct of all Crown mining goes to Throne operators, the remaining 60pct goes to typical crypto miners)
2. They make the Crown network more decentralized and therefore secure
3. They will be also used as a backbone platform to build several applications on the Crown network
4. You dont need a supercomputer to mine CRW - with Thrones you do it with cloud VPS with a minimum cost - therefore anybody can set them up - the system is therefore more democratic
5. You need a 10k CRW as collateral to set up one Throne (this way CRW is kept away from the market and capitalization will grow)
6. One Throne currently pays around 20USD per month

You can see more info - how to set them up, income prediction, etc. here:

http://www.crowncoin.org/crowncoin-mining.php