Short-form writing on Twitter isn’t simply about writing something useful or interesting in 140 characters or less.

It’s also about writing within a medium that is transitory.

While your Tweets from last week may be archived way back somewhere, they are invisible.

You are what you are writing about now. You are as interesting as your last twenty Tweets. As useful as your last twenty Tweets.

This may be not be a problem for someone using Twitter simply for pleasure. But it presents an interesting challenge for companies and professionals.

It’s a little like standing on a beach and watching the waves roll in. Each wave breaks and unless there is another wave following, the show is over. Like a wave, your individual Tweets have a very short lifetime.

So you need to keep them coming if you want your audience to keep watching and reading.

From a branding perspective, this is very weird. Or rather, it’s a big change.

Brochures and web pages are pretty permanent. Say what you want to say once, and your message is there for all to see, tomorrow, next week and next month.

Not so with Twitter. Say what you want to say now and the message will be lost and gone within a few hours.

This means you have to continually repeat your branding message, but without repeating yourself.

Now this gets more interesting.

Why? Because while you can write a permanent positioning or brand statement for your brochure or website, you can’t keep repeating the same sentence on twitter.

In other words, your brand can no longer be articulated as a single, permanent statement. It has to be expressed within a continuous flow of new, fresh and engaging Tweets.

You are no longer what you say you are. You become what you show yourself to be.