Memcached is a high-performance, distributed memory caching system designed to speed up dynamic web applications by reducing database load. It stores data and objects in RAM, allowing for lightning-fast retrieval compared to traditional database queries.

When a user requests information (like product details or user sessions), the application first checks Memcached. If the data exists there (cache hit), it's served immediately. If not (cache miss), the application fetches it from the database, stores a copy in Memcached for future requests, and then delivers it to the user.

Key benefits for hosting and websites:

• Reduced Latency: Data from RAM is served in milliseconds.
• Database Offload: Decreases direct queries, preventing bottlenecks.
• Scalability: Easily scales horizontally by adding more servers.
• Simplicity: Uses a straightforward key-value storage model.

Common use cases include caching:

• Database query results
• API responses
• Session data
• Rendered page fragments

To implement Memcached, you typically install the Memcached service on a server and use a client library (for languages like PHP, Python, or Ruby) in your application code to connect to it. Remember: since data is stored in volatile memory (RAM), it is temporary and can be lost on a server restart—it's not a permanent data store.

For optimal performance, monitor cache hit ratios and allocate sufficient RAM based on your application's needs. When configured correctly, Memcached can dramatically improve your website's responsiveness and handle increased traffic efficiently.