R – Windsor Castle: good sources for documentation, tutorials

It adds custom dependencies (tags) to the component being registered. The WcfFacility, for example, uses these attached dependencies to set up endpoints and other stuff.

It really depends on how you structure and name your components... if you keep some simple conventions (i.e. all component services under the "MyApp.Services" namespaces and their implementations under "MyApp.Services.Impl") you could dramatically decrease this complexity (see for example ayende1, ayende2).

Also, IMO the usefulness of this is rather limited except for the most simple cases... for example some services you want to register without any service interface, some services need configuration, service overrides, etc. in which case this won't work.