It's not uncommon these days for your web site to
include lots of different types of information from
lots of different sources. If it's not already,
one of these sources will probably soon be a remote
web server. While this type of information exchange
can be a valuable asset, it can also be quite a bottleneck.
With client internet connections getting faster every day,
slow response times can really hurt your site's perceived
quality. If you're making an HTTP request with every request
it's almost certainly slowing things down.
Luckily many things are much faster then making a connection
to another server. These include application variables,
the file system, and local databases. Storing information
in one of these locations when you initially retrieve it and
using it for future requests can dramatically speed things up.
While this obviously won't work for applications that require real-time
data exchange, for many applications it works great. Even a
relatively short caching time (like 15 minutes) can have a
dramatic effect on a high traffic site. If you serve 100
pages in those 15 minutes then you've saved making 99 slow
requests to the remote server!