The potential of the internet as a sales vehicle is to face a new test this weekend as the first online contemporary art fair is launched. The VIP (Viewing in Private) Fair will be the nearest to the prestigious Frieze or Art Basel fairs you can get without actually going there. Almost 140 galleries, including some of best known internationally, will be presenting 1,928 works of art for one week only. The idea of the fair was conceived three years ago by New York dealer James Cohan. "Economic depressions tend to encourage ingenuity," says Cohan's wife, Jane.