Question : different between use POP3 , IMP4 and http

hi
when i made  outlook configuration i need to know what is the different between use POP3 , IMP4 and http


thanks

Answer : different between use POP3 , IMP4 and http

POP3:
http://en.wikipedia.org/wiki/POP3.

IMAP:
http://en.wikipedia.org/wiki/IMAP