User-centred design (UCD) is a project approach that puts the intended users of a site at the centre of its design and development. It does this by talking directly to the user at key points in the project to make sure the site will deliver upon their requirements.
The stages are carried out in an iterative fashion, with the cycle being repeated until the project's usability objectives have been attained. This makes it critical that the participants in these methods accurately reflect the profile of your actual users.