Every application runs its own holochain, on its own terms, without the need for expensive hosting overhead. Since users are the hosts, as more agents begin using the app, more storage becomes available.
The “DNA” of an app comprises the first entry of an agent’s source chain. These rules set validation requirements ensuring that the application runs securely: that data cannot be counterfeited, tampered with, or lost. An app’s validating DHT randomizes redundancy of public data across nodes in the shared space. When nodes go offline, the DHT continues to maintain the data necessary for the app to perform. And if someone changes the app rules they write themselves out of the shared DHT into an entirely different application.
from
Holochain website 
