As you know, many Android mobile applications are in direct dependence on Internet traffic. No internet - applications do not work or do not work properly. At the same time, some of them may be "eat" the traffic in so-called background. The result is that the user does not sign up to the Internet, and megabytes left.
To avoid this, try to disable synchronization. To do this, press «Menu», while on the desktop, then "Preferences" / "Data synchronization". In principle, you can disable and background data, however, in this case, some applications such as Google Play may stop working.
In general, the frequency of the output of programs in the Internet are usually configured directly in the program menu. For example, Google Talk is an automatic entry in the "weather" is set to "Automatically update" on Facebook and Flickr - «Automatically update every application ..."
If you have limited traffic, we recommend to protect yourself from it overrun with special applications. Here you useful programs such as APNDroid (you can disable access to the Internet), Droid Wall (also blocks access to the Internet, you need the right root), Data Counter Widget (counts traffic), 3G Watchdog and many others.