What’s the difference between distributed hashtable technology and the bitcoin blockchain?

• A DHT is simply a key-value store distributed accross a number of nodes in a network. The keys are distributed among nodes with a deterministic algorithm. Each node is responsible for a portion of the hash table. A DHT is very scalable because the data are uniformly distributed among nodes.
• A blockchain is also a distributed data structure but its purpose is completely different.Think of it as a history, or a ledger. The purpose is to store a continuously-growing list of record without the possibility of tampering and revision.

In a blockchain, each node of the network stores the full data. So it is absolutely not the same idea as the DHT in which data are divided among nodes.