Wikipedia, the collaborative internet encyclopaedia, is about to get some competition. On 17 October, Larry Sanger, who helped set up Wikipedia in 2001, announced the launch of a site called Citizendium and declared his venture 'will soon attempt to unseat Wikipedia as the go-to destination for general information online'.

Since 2001 Wikipedia has grown from a small, well-meaning venture into one of the world's most popular websites. It relies on users to generate its content and, as a result, its 5m pages of information have grown exponentially, providing a continually evolving, instantly available (and free) reference source covering a vast array of topics.

Sanger, who left Wikipedia shortly after its launch, is motivated both by the desire to offer an improved alternative and the need to score a personal victory against his former partner, Wikipedia founder Jimmy Wales.

Which will emerge as the dominant internet encyclopaedia? In the dotcom world, where there is little customer loyalty, the battle for market share can be swift and brutally conclusive. It looks like shaping up into a classic confrontation between two organisations that have a lot in common in terms of product, but come to the market in very different ways in terms of strategy.

Wikipedia is the first mover. It created the category and as a result enjoys a number of strategic advantages. First, it has already built up a great deal of residual brand equity. Wikipedia is up there with Google and eBay as one of the most familiar sites on the planet. It also has the advantage of the brand associations that come with being the original and authentic web encyclopaedia. Coupled with this are the operational competencies Wikipedia should have built up. As first mover, with millions of users, it should also have learned a lot about its market and be better placed to satisfy their needs in the future.

If this were 1999, I would be declaring Wikipedia the unassailable leader in this category. Then, marketing professors and analysts believed that being first to market, especially online, was vital to future success. But in recent years it has become clear that there are at least as many strategic advantages from following the leader into the market. The so-called second-mover advantage, of the kind enjoyed by Citizendium, could prove ultimately more powerful.

Second movers can avoid heavy investment in research and development by replicating the first mover's approach. Citizendium will start life as a 'progressive fork' of Wikipedia, opening up as an exact copy of its site, saving itself five years of development time, and evolving from there.

Second movers also enjoy the advantage of positioning. Sanger knows exactly how Wikipedia is perceived in the market. He is using that data cleverly to aim Citizendium at what he calls 'different social niches'.

Best of all, it can learn from its forerunner's mistakes. Citizendium is introducing developments such as site sponsorship and an editorial team of expert academics to improve accuracy. These initiatives should help it avoid many of the pitfalls to have befallen Wikipedia.

Whoever wins this battle, we should spare a thought for the market's real first mover - Encyclopaedia Britannica. Despite an overall head-start of more than two centuries, its online version is being eclipsed by Wikipedia, which has almost 60m users compared with Britannica's 300,000. When it comes to first-mover advantages, it all depends when you start the clock.