Does anyone know how to lock down a user just from downloading artifacts from the site?  I can’t seem to be able to refine the security enough to provide this.  I want a user to be able to browse, but not download.

Sorry for being dense but, what is a "build artifact repository manager"? and why do I need one?

I’ve downloaded and run it. It appears to only hold a junit jar and nothing else.

I use both Maven2 and ANT but, what am I supposed to be doing with Archiva? What does this web app actually do?

Hi, a build artifact repository manager is a tool you would use for managing and hosting your internal (local network) repositories and use these repositories for your build (as proxies of remote repositories). When building maven 2 projects, you could set up in your settings.xml file to have Maven get the artifacts that you need from the above mentioned proxy repositories.
 
Aside from the above functionalities, Archiva also has other features such as repository search & browse, repository purge (that is, cleanup your repository of old snapshots), finding unknown artifacts and reporting.

I hope this somewhat answers your questions =) There’s also documentation available on the web site if you need more details.

Thanks!