Using mod_gzip compression which is an Apache web server module, or one of the other methods of gzip, your server will only send out gzipped content All the new browsers currently in use support gzip. Incase an old browser which doesnt support gZip makes a request, uncompressed HTML will be served.
gZip will work on the following file types: HTML, JS, CSS, JSON, XML
Some advantages of Zipping your data
To check if your site is sending gZipped content or not, use these links
If your server is not sending gZipped data then you can write to your server/hosting company and ask them to enable mod_gzip on the server. You can also tell them the advantages of doing the same. Dreamhost/Mediatemple already has this module enabled. If you are running your own server please ask the system administrator to enable it for you.
More tips coming up soon.