I have noticed that if you leave a Youtube tab open in firefox the network traffic ramps up until it consumes all of our broadband. You have to kill all of the firefox windows to stop it. Anyone know what is happening when this happens?
It may not be specific to the Linux version. Herewith a brief digression and a cautionary tale:
Last week I left a tab open on my XP /Firefox box - monitoring one of the Prague webcams at the time. Visitors called - hospitality took priority.
When I next checked about 3 hours later, nearly 20% of my monthly quota had gone in that exercise. ( I am a miserable sod and usually get by with 5Gb a month - but this was a real shock

)
I use the nifty little Net Usage Item for FF, but it doesn't help if you don't monitor ....
Back to the specific Linux issue now ....
f_o_r