These are not actually two different pages. The first one (uppercase) provides an overview of the l10n effort, describing different things: how to get Debian installed in Spanish, what documentation is available, etc... it is targeted towards end users. Although some of the information, I admit, is out of date.
The second one is the l10n coordination page, describing the different aspects of the project. It is targeted toward translators (or people interested in becoming one).
The first one links to the second one when talking about project activities.