Spirits in the Wires — Charles de Lint

At a popular Newford on-line research and library Web site called the Wordwood, a mysterious crash occurs. Everyone visiting the site at the moment of the crash vanishes from where they were sitting in front of their computers. Christy Ridding's girlfriend, Saskia, disappears right before his eyes, along with countless others.

To rescue their missing friends, Christy and his companions must journey into Newton's otherworld, where the Wordwood, it transpires, has a physical presence of its own…