Twitter - Shitter more like

I just don't get it - I know that it's supposedly a great marketing tool, and that you can use it to send up to 140 characters of information about your life to any number of people who might not otherwise know what you were up to all the time. But I don't get it - I can't follow anyone unless I know their e-mail address, and if I knew their e-mail address then I'd probably just e-mail them to ask what they're up to. I know my brother 'tweets', and I am constantly reading long earnest articles about how important it is to avail yourself of all the social media you can get your hands on lest you miss some important snippet of information, come late to a discussion about your niche or find that someone has tweeted something you disagree with and you're not the first to comment. I am sure I will get into it - it's my first day after all, and because I am doing it for work, I can't really just get fed up and jack it all in, but I really can't believe that it's more efficient just to e-mail the people you know and tell them that you're 'feeling slightly sick' or any of the other gems I have seen on there so far...