What's a dht node? I saw some people talking about that but I didn't really understood what they were meaning.
A distributed hash table (DHT) is a distributed system that provides a lookup service similar to a hash table. What differentiates a DHT from a normal hash table, however, is the fact that storage and lookup on DHT are distributed across multiple (can be millions) nodes or machines, and the node that gets to store a particular key is found by hashing that key, so in effect, your hash-table buckets are now independent nodes in a network.
What are some reasons you'd want your hash table to be distributed?