I know some people might be thinking "Why should anyone write about public speaking online? More importantly, why should I read it? And where are my pants?" These are valid questions--where are your pants? Most people would probably rather watch Carrot Top gargle hedgehogs than spend time public speaking, and so they don't see the relevance. But the truth is that you can't get away from speech. It's still one of our most basic forms of communication, it's a huge cultural touchstone, and I'll argue that its skills translate into more than just corporate earnings reports and geeky undergraduate competitions.
If nothing else, learning to speak well makes you a better writer. Many good writers already speak well, so they don't initially see the connection. Yet as I will point out later, writing for the page and for the spoken word can be very different disciplines. But in general, the kinds of tricks that you learn when writing a good, easily-understood speech in terms of phrasing, structure, and audience appeal will serve you just as well in print. They'll certainly help with editing.
But consider this: as certain parts of our culture mutate in response to the Internet, one of the innovations in online style has been the use of punctuation and capitalization to mimic the rhythms of verbal conversation. Not that this is entirely new, since books and articles have been written in the vernacular before, but I think the casual tone of blogs and chat have helped to turn what used to be dialect showboating into actual conventions. See Heather Armstrong, AKA dooce:
Armstrong isn't the only person to do this, but she's a good example and most people online have probably heard of her. The point is not that this is great writing, although I think dooce deserves a lot of credit. What I'm trying to point out is that as culture has moved online (and that means text-based, despite the hype around podcasts and video blogs), our use of that text is moving in a couple of different directions. One is that lazy IM-speak that causes despair among high school educators worldwide with its brb, lol, c u l8r nonsense. The other is a definite trend of casual communication, which I believe comes partially in response to the dry and impersonal nature of the medium. It is writing that evokes speech, hand in hand with the "conversation" of a good blog/comment system.
But even if you're not a writer and you don't want to be a writer (I sometimes forget that not everyone enjoys hitting the keyboard as much as I do), I think you might still find some of these tips useful. Good public speaking is as much about the rhetoric as it is about the delivery, and today we find ourselves surrounded by rhetoric--ads in everything, an accelerating presidential election, news coverage that's barely news or coverage. The best way to avoid being fooled is to learn how to do it yourself.