Broadband Phone Useage - I haven't got a broadband phone

[#1]

Folks - can anyone shed any light on this one. I'm a bit of a technophobe but I am trying and I've been keeping an eye on my usage. I've just looked at the breakdown for the first time and a large chunk of my internet useage is shown as Broadband Calls.  I haven't got an internet phone and only use my laptop to access the internet, so how am I racking up broadband calls?
Cheers folks! 

[#2]

Do you use Skype or online voice/video calls?
In fact, I've just taken a look and the amount of data shown for this category are tiny, so it's most likely just background traffic. I wouldn't worry about it.