Cloud mining is the process of cryptocurrency mining utilizing a remote datacenter with shared processing power.

This type of cloud mining enables users to mine bitcoins or alternative cryptocurrencies without managing the hardware.
The mining rigs are housed and maintained in a facility owned by mining company and the customer simply needs to register and purchase mining contracts or shares.

Since cloud mining is provided as a service, there is generally some cost and this can result in lower returns for the miner.

Polkadot is a blockchain platform and cryptocurrency. The native cryptocurrency for the Polkadot blockchain is the DOT. It is designed to allow blockchains to exchange messages and perform transactions with each other without a trusted third-party. This allows for cross-chain transfers of data or assets, between different blockchains, and for decentralized applications (DApps) to be built using the Polkadot Network.