While browsing internet or more specificaly while opening internet sites all of you must have seen in the url's(uniform
resource locator) say for eg.
http://www.google.com
is the url of google server.
the url of a web server is same as we have home address.
all url's by default start with either http:// or https:// depending on the server we use.if we don't add them before a url
then our web browsers add them by their own
Now the question arises what are they ,for what purpose they actually are,and what is the differnce between them?
http://  stands for hyper text transfer protocol,while https:// stands for hyper text transfer protocol(secure),the 's' here
is indicative of security of web page.
A protocol in computer's world mean a set of instructions to complete a particular task.
http:// and https:// both are protocols for sending and recieving data over the internet.
The data we send includes the things which we search in search engines like google and yahoo,and id's and passwords we send while banking processes etc.
now you must have thought that searching google and entering secret password are same things ie we are sending data but their privacy levels are very much different.
General web sites which do not deal with such private data like search engines,wikipedia etc,their url's start with  http:// 
while the sites dealing with private sites like banking related sites .their url's start with https://
the main purpose of using two types of protocols is to provide an additional layer of security to web users ,so as to save
them from financial as well as other types of losses.
The urls starting with https:// are also difficut to hack it serves an additional advantage.
so next time while entering any private data into web sites check their security levels themselves by checking http:// and
https://
thanx a lot hope you will find it useful.