Network WINS setting

Hi,

Bit useless with computers and technology and just had a question. Just was having a look at the advanced network settings on my MacBook. Underneath the 'WINS' heading, it shows a series of workgroups and I'm kind of confused as to what these are/what that means? Are these ones that are available for me to join or are they something my laptop is sending out for other people to try and get onto my network with?

Thanks.