Netspeed is an applet for the GNOME panel that shows how much traffic occurs on a network device (ethernet card, wireless LAN card, or dial-up).So, It is a very important tool for everyone. You should use it when you love to hangout online whole day.
You will get in 'Ubuntu Software Center' or in 'Synaptic Package Manager'. Search 'netspeed' and install it.
Change some common preferences is quite easy.
Right click menu on the icon show original menu or this application itself.
You can change some Generel Settings from preferences dialogue box.
Run it in several way. I am telling you the only best and recommended way.
Click Add to Panel on anywhere in the top panel. You will get it in the N area of this alphabetical list. Click on 'Network Monitor' to select it and click on Add. Everytime you start computer it will start automatically and be ready to do its job. Connect internet or any network it will start to show data / information instantly.
Netspeed Official Website