IBM is an open source community of various Blockchain projects. It is an umbrella strategy for developing enterprise based solutions.
IBM's Hyperledger projects is being widely used for implementing blockchain solutions.
Here are some practical implications of blockchains
https://www.ibm.com/blockchain/au-en/business-use-cases.html
Data is stored in blocks and how the proof of work is achieved and the immutability of data are the new concepts of blockchain.
Blockchain is a decentralized database distributed across the network
Blockchain always only stores the hashes of the data.