If you look on the left hand side of this web page you’ll see a small grey tab with ‘tweets’ written on it; this is my Tweetboard, where Twitter users can log in and post to Twitter. I think they are working on one for Facebook, too. All you need to do is click on the tab:

You’ll then see the board slide over, where you will be prompted to sign in with your Twitter account:

Once you’ve signed in, you can post stuff right from my site. Cool, huh?