I have for a long time now been a fan of Wikis. I use them for project based communication mostly as they provide a very informal way of creating and linking intranet style information. But that is the limitation, they are scoped to the containing implementation and although most Wikis allow you to provide certain external links they are usually to a fixed set of sites as URLs and not extensions of the Wiki environment.
LocalNames - OneBigSoup is a project designed to join Wikis together. If you use wikis then you will know that normally when you reference some external concept you either have to use the URL at each place it is referenced (which can be a maintenance problem) or you create a local abstraction of the remote URL which takes time and effort to set up. LocalNames gives you the latter without the setup cost. To take an example, a corporate project based Wiki that would normally evolve links to all the external technology and business related sites it uses and avoid that by referencing the company Wiki that already has the links in place.
As the OneBigSoup team will readily admit, LocalNames can only go so far. The search for a name can be very extensive and name spaces are not mutually exclusive, administrators would need to be careful about which namespaces they import and so on through the chain. Luckily you can control the depth of the search.
Another potential shortcoming is that Wikis are designed to be easily accessible with community based posting etiquette. With LocalNames Wikis would tend to get smaller in size and scope, which means that the security privileges of users will be equally reduced. There is a need to be able to have friendly Wikis so that the contributing users are not increasingly restricted by a modular Wiki environment. It would be a real headache to have to login to multiple Wikis and maintain usernames and passwords in multiple locations. And as yet LocalNames does not address this issue.