It is the Web’s second coming — at least so say the apostles of Web 2.0, the so-called second generation of Web-based products and services that emerged in the wake of the dot-com collapse.

Web 2.0 sites often bear a close resemblance to desktop applications but with the Web as their platform. Word processors, calendars and spreadsheets are just some of the traditional desktop applications offered online under the Web 2.0 rubric.