html,shtml,htm

[Pattielli]

What are the differences between them ?
Another question, sometimes I see some internet addresses like http://FalseWebpage.com/
why isn't there www before FalseWebpage ?

Thank you,

[Anttech]

html = hyper text markup language
shtml - html that is using sever side includes
htm = abbrivation for html

DNS (domain name system) works by translating a URL/domain name to an IP address.... There is no need to put a www in front if the domain point to the web service rather than lets say the SMTP service that this domain is hosting....

Your question cant be answered in a short post... Sorry to say this but you should RTFM on this one :-) I would suggest you read some RFC's for example RFC 1034 which describes DNS... If you have a grasp on DNS then you will understand why you do not need to put www in front

http://asg.web.cmu.edu/rfc/rfc1034.html

[Greg Bernhardt]

www is actually just a folder on the web server, information inside needs the www, information outside doesn't. It's just become a standard overtime to include a www folder as a formality.

[Anttech]

actually www is the bottom level in the DNS name (Domain Name) .com being the top... a folder would come after the .com for example

www.google.com/myfolder_file

A web server could just as easily sit at

abcd.google.com
fghy.google.com
whatever.google.com
whatever.whatever.google.com

As long as you have a DNS zone per level specified on your name server you can go as far as you want...