[Geowanking] metadata implementations

[Tim Bowden]

I'm looking for examples of large(ish?) spatial metadata systems that
have either been successful or have tanked (ok, that should open the
field up a little).  If you are able to point me in the direction of
such (along with any ideas as to why it was successful or not), that
would be great.  Note, I'm specifically not looking at metadata tools.
Just projects that tried to implement such a system.

Thanks,
Tim Bowden