alright, if you understand "blogging", which is basically writing a diary and posting it for the world to read, with no responses expected, "twittering" takes it to the next level, you write a "short" blog, then a mailing list is notified, i.e, the message "I just sneezed" is sent to 2.3 million people automaticaly

I should add that blogging is mainly an internet thing, where as twittering is a cell phone thing