The Open Directory Project now has over two and a half million sites organized into more than 370,00 categories. Taxonomy, the subject hierarchy of categories, becomes something all editors learn the rudiments of as they learn which sites belong in the categories they edit and which sites belong elsewhere in other subject strings in the ODP.

Subject areas are created, grow, and recede into obscurity as users respond to changes in science, the arts, and popular culture. And as interests wax and wane, the ODP taxonomy must adapt to new subjects, new interests, and an influx of newly created sites. Reorganization of taxonomy strings is a constant in the ODP, from the major "reorg" to the minor adjustment of small subcategories.

Recent major reorgs included one about as major as it can get, with Kids and Teens sites moving into a brand new, top level category with its own logins, guidelines and independent editor community. Responding to a special patron community with its own needs, this reorg allowed editors to think how best to present useful information to our youngest, and most vulnerable, users.

Only slightly less extensive in the last year have been major reorgs of the huge Regional and Shopping categories, involving dozens of editors contributing their expertise and opinions to reorg threads, category descriptions and guidelines.

The fallout from major reorgs, as other parts of the ODP respond to big changes, can go on for some time. Recently, a group of editors took on the difficult task of reorganizing the History taxonomy, which had outgrown its original construction as the ODP grew.

Several attempts had been made earlier at the difficult task of organizing historical information in the ODP. History is a subject of broad interest to different ages of patrons and different levels of expertise. Organizing such a category to be responsive to sites designed for users from the fourth grade through graduate school, from the academic to the interested layman, from 5,000 BC to 1999, from Afghanistan to Zimbabwe, was no easy task.

The Regional reorg provided one piece of the puzzle as editors contemplated the possibility of organizing at least some historical sites by region. The Kids and Teens reorg provided another piece of the puzzle, as editors determined that they could organise children's historical sites and subjects separately from other user populations.

There was still much to be done, however, as editors tackled organizing history so that it could be approached by time period and by topic. Although much has been accomplished, this reorg continues, as history editors patiently work their way around the world and through time.