Document caching with <meta> tag

Because caching involves keeping a local copy of a web page or embedded objects (such as images or media files) on a proxy server or local disk drive, it can help reduce redudent network traffic by avoiding fetching of a new copy of the document from the website. Caching can be useful when

1. the content of the site does not change very often, and
2. many vistors access the website or web page that does not change very often.

If you think about it, you would not want to fetch the same page over and over particularly when its content does not change very often. Thus by avoidign to fetch the same page over and over, you can reduce network traffic.

Caching may sound like a good idea and it may be used too aggresively. If pages are cached too agressively, then, users may inadvertanly view old content.