Caching

 Excellent article on caching on http://www.mnot.net/cache_docs/

What’s a Web Cache? Why do people use them?

1. Kinds of Web Caches
   
   1. Browser Caches
   2. Proxy Caches
2. Aren’t Web Caches bad for me? Why should I help them?
3. How Web Caches Work
4. How (and how not) to Control Caches
   
   1. HTML Meta Tags vs. HTTP Headers
   2. Pragma HTTP Headers (and why they don’t work)
   3. Controlling Freshness with the Expires HTTP Header
   4. Cache-Control HTTP Headers
   5. Validators and Validation
5. Tips for Building a Cache-Aware Site
6. Writing Cache-Aware Scripts
7. Frequently Asked Questions
8. Implementation Notes — Web Servers
9. Implementation Notes — Server-Side Scripting
10. References and Further Information
11. About This Document