how to interpret the system tray icon

the system tray icon sometimes shows a single yellow arrow pointing down, and sometimes a series of yellow arrows pointing down.
the same is true with the green upward-pointing arrow.
what does all this signify?

Traffic animation. Yellow is download/received traffic, green is upload/sent. The amount of arrows indicate speed so 1 KB/s or less (think Bytes/s) is 1 arrow, 2 KB/s 2 arrows, and 3 KB/s or more is 3 arrows.

@futuretech is right.
If you did not like it, you can disable the “traffic animations” on firewall settings.

thanks guys
do you see any security value in this, or is it just to let you know when there is traffic?

I guess if you’re paranoid you can use as an indicator that something is going on if you’re not doing anything that would use network traffic, though it most likely will be traffic for auto-updates for programs and for windows. But yeah it would just let you see at a glance whats going on in regards to network activity.