Media Perspective: It's effective online marketing Jim, but not as we know it.

Millions of miles away, in the far north of Mars, the greatest marketer of this young century is slowly dying in the cold and dark. A dust-storm is covering its photovoltaic panels, its power is draining and NASA has switched it into 'Lazarus' mode. The long Martian winter is setting in, we probably won't hear from it again.

If you're one of the 40,000 people subscribed to the Mars Phoenix Lander's twitter stream, you'll know exactly what I'm on about. The rest of you might need some explanation.

Let's start with twitter. It's a simple service that lets you tell your friends (and other interested people) what you're up to in 140 characters or less, via your phone or computer. It started off as a person-to-person thing, but, fairly quickly, all sorts of other stuff started to get squeezed down the twitter pipe: news headlines, the shipping forecast, news of whether Tower Bridge was opening or not. And, back in May, the Mars Lander was added to the list.

It started as just another bit of the NASA effort to get the world interested in space again. A Jet Propulsion Lab staffer was asked to submit twitters on behalf of the Lander, but she did it so well, working in her own time, adopting an energetic first-person voice, that she amassed an enthralled audience of 40,000 people - all for a media cost of zero.

The Mars Phoenix Lander is a textbook example of how to use social media tools to delight an ...