Linux: What programs are accessing the Internet

So, I am starting to worry a little that something or someone is hacked into my Linux Laptop. I have installed a network Gnome Extension that displays size of bytes going up and down on my Internet connection. My laptop seems to be talking to some program on the internet I don't even know what it could be talking to. There is always some bytes (10 - 50kb every 4 seconds) on the average being received and transmitted. This happens even when I got no applications running on the system like FireFox. Thinking that my laptop has been hacked, I completely reinstalled my Linux OS and still it is showing that there is always some bytes going up and down the Internet. I did do the netstat -all command on the terminal but that doesn't really show much and it looks way to cryptic. I want some program like Etherape program. Etherape is too confusing to use. What do you suggest? I need to know what program is transmitting and receiving bytes on my Linux system. ANSWER Using netstat -an you will see which ports that are in a connection at the moment. If you want to see which process that is connected to a certain, port 80 in this case, you can use lsof -i tcp:80 Well, you need to be root, of course