Internet connectivity on mobile phones, or data plans are costly, and are often bandwidth capped or speed limited or both. This is why Opera Mini is so popular among mobile phone users. The Opera Mini browser employs a technology called Turbo that reduces bandwidth cost of the users by pre-rendering pages on Opera’s server and sending highly compressed version of the page to the user.
It should be noted that only HTTP traffic is routed through the proxy servers. Secure (HTTPS) requests will bypass the proxy and continue to connect directly to the destination. So on an sites that uses HTTPS such as Facebook, Gmail, Twitter etc. you can’t save any bandwidth by compression. Furthermore, since DNS lookups are also performed by the proxy, it automatically enables Safe Browsing.
The data compression feature is now up for testing. To checkout the new feature, first install Chrome Beta for Android from Google Play, then type chrome://flags in the address bar and tap "Go".
"Enable" next to the "data compression proxy" experiment, and once enabled tap "Relaunch now" to restart the browser.
To see how much data you've saved type chrome://net-internals in the address bar and tap on "Bandwidth" in the left sidebar. You can refresh this page any time to get updated stats on bandwidth saving.
via Chromium Blog