The development of electronic marketplaces ahs been prolific in the last five years and the pressure for companies to participate, before they have determined how to recognise the benefits and pitfalls, has been intense. This has left prospective participants facing a wide variety of choices in the selection of potential trading sites, in a marketplace that is both dynamic and immature. Although there are different drivers pushing companies towards participation, an appreciation of how electronic marketplaces are developing their trading models can support the selection process and enhance the trading experience of the participants.