What causes network data use besides automatic updates? Yesterday I updated my old OS to Yosemite. I saw that automatic updates were using a lot of data so I turned them off them off in System Preferences. After restarting my computer, I checked Activity Monitor > Network, and Received Data shows 1.67GB

What uses data besides automatic updates? Is there a way to reduce the data usage?
All right guys, I found the solution. I went to Finder > Library > Updates then I saw the bunch of update files their. So, I had deleted all those files and connect to Internet. Well, now it is OK. :D