I would be very happy if any body can really help me distinguish between lan, and wan. yeah am aware lan and wan means local area network and wide area network respectively and also man means metropolitan area network but I need a clear difference
and also which one can be used for video conferencing?

It's like Google have started charging people for using it

MrPdtech:
It's like Google have started charging people for using it

yeah Google will deliver a confusing answer
and for video conferencing google didn't give me that

Local Area Network-is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building. 

Metropolitan Area Network - is a computer network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network but smaller than the area covered by a wide area network.

Wide Area Network -is a telecommunications network or computer network that extends over a large geographical distance. Wide area networks are often established with leased telecommunication circuits.