Normally when brand marketing is said to be out of this world we assume it has been a raging success. For several brands that have created a presence for themselves in the virtual world Second Life (SL), however, the otherworldly experience hasn't been as impressive as they would have liked.

Coca-Cola - one of the biggest brands in Second Life - has recently made a quiet exit from SL. It isn't the only one to question whether the benefits of marketing on SL outweigh the costs. Others, however, remain confident SL will pay off.

SL was launched in 2003 and soon made headlines due to its explosive growth. People taking part, the so-called residents, create 'avatars' that can be moved through the digital world and interact with other residents. SL is free to join, but those that are really serious pay to buy land and build on it in a way that lets them act on their creative urges.

Hype reached such a level that well-known brands rushed to establish an SL presence. Most did so to glean an understanding of consumers in this surreal environment far removed from traditional marketing channels.

They soon found themselves facing very different challenges to those in the real world. Car maker Nissan, for example, had to rebuild its presence there after virtual terrorists crashed a helicopter into its SL building, while the store of clothing retailer American Apparel was attacked by armed militants. This isn't the unthreatening world of Super Mario land - there's an edge to it.

The edginess appeals to brands wanting to try something new. Hotel group Starwood introduced its new brand, Aloft, in SL last year ahead of its real world debut in 2008.

"You can test things in a virtual world before creating it in the physical world," says Marc Schiller, CEO of digital agency Electric Artists, which worked with the hotel group. "The cons are that the barriers to entry for most people into virtual worlds are quite high. Second Life is far from being user friendly. Today brands can only reach a miniscule number of people inside a virtual world."

He's not exaggerating. Though SL boasts 1.4 million residents logging in over a 60-day period, at any given time the number of active residents can be quite small: 32,000 and 40,000 the last two times The Grocer checked. Conversely, the world itself is huge and growing, making it difficult to pull in visitors to the brand's area - as Coca-Cola found out.

The biggest brand yet to have experimented in SL, Coke launched a 'virtual thirst pavilion' last April inviting residents to design the drinks vending machine of the future. The response, however, was lacklustre and Coke unexpectedly withdrew from SL after the promotion. The fault was more Coke's than SL's, suggest experts.

"Coca-Cola was one of the first mega global brands to enter Second Life and try to make a big, lasting splash," says Leigh Rowan, vice-president interactive at marketing agency TheSLAgency. "Its engagement in SL did not resonate with SL residents. They were not marketed correctly in-world and they were not adequately prepared. Think of SL as another country: you must know the customs, the language and the currency of another country before doing business there."

Brands need to create compelling reasons for people to visit their SL space and update and innovate to keep people coming back, says Rowan. They also need to use the right partners, says Joni West, president of another specialist agency, This Second Marketing.

"The brands that were disappointed with marketing in SL typically went to developers who had no background in marketing, just building virtual things," she says. "So they built beautiful 'sims' or brand islands and no-one showed up."

Both agencies are working with Nestlé brands at the moment, TheSLAgency with Nesquik on understanding how consumers interact with brands and how this informs retail sales and This Second Marketing with Coffee-mate on an SL cafe venue.

Nestlé isn't the only one testing the waters and some have already enjoyed success. Unilever's Ben & Jerry's boasts that more than 2,000 people visit its island every week to play the games it has created, and participants may later move to other parts of SL wearing Ben & Jerry's T-shirts, which provides the brand with further marketing exposure.

L'Oréal, meanwhile, has run a competition to find the virtual face of the brand in SL and has partnered with established SL retailers to give its products exposure. And Boots' No7 brand has been offering SL's female residents the opportunity give their avatars a makeover.

"While they are at a very early stage of adoption, we have no doubt that virtual worlds will play a larger role as a communication vehicle in the future," says Boots head of brand development Helen Tarver. "We wanted to test the waters with some initial activity."

A second phase of activity in SL is due to go live in the summer. Despite her enthusiasm, Tarver admits she has been disappointed by the large number of people who drop out of SL after creating an avatar and taking their first steps on Orientation Island - 90% don't return.

It is this that has dissuaded others from joining SL. "It is not something that is high on our priority list right now," says Cadbury Schweppes interactive and emerging media manager Fran Dovey. "The strength of the internet lies in its sheer utility - ease of use, time saving, instant communication and connection. At the moment Second Life doesn't seem to be able to tick all these boxes and only truly appeals to a smaller portion of users."

For now. In many ways SL resembles the early days of the internet when online marketing was hit and miss. Although Coke may have had second thoughts about Second Life, other brand owners remain confident that a virtual world will deliver real benefits - one day.nDO's and DON'Ts

DO - investigate what has succeeded in SL and what has not

DO NOT - expect immediate sales uplift in the real world

DO - create experiences that ensure participants return

DO NOT - confuse clever SL gimmicks with good marketing

DO - partner with other SL retailers for brand exposure

DO NOT - assume your brand's status in the real world will translate into the virtual world

DO - push the limits and use SL to innovate and experiment beyond your brand's normal boundaries