What is VLAN?

[HiThere1234]

I saw the term VLAN on the ubiquiti edgerouter lite specs sheet. What is VLAN and what does it do?
What are the advantages and disadvantages?
and What is it used for? Is it viable for home network application?

 

[i7Baby]

Virtual LAN - http://en.wikipedia.org/wiki/Virtual_LAN