For RailFans, Platform Announcements are more musical than Bollywood songs. - Prince Maan

There are 2 types of tickets that can be booked thru irctc.
i-ticket is like a normal ticket which you get in any PRS. Once you book, they will courier it to the address given by you. The passengers will not need to carry any ID proof (except for tatkal for which all passengers from 11th Feb will need to carry ID proof). This ticket needs to be canceled at PRS if need be and the money is credict to the account which was used to book tickets.
e-ticket is a print...
more...

out which can be used to travel. One passenger should carry ID proof(all for tatkal). This ticket has to be canceled online. Once chart is done you will need to find a TDR to cancel. If e-ticket remains WL after chart is prepared it is automtically canceled by irctc.