SERU registration question

["Bahnmaier, Sara" <sarabahn@umich.edu>]

I'm curious, can someone please tell me if a publisher and/or 
institution MUST be registered for SERU in order to use it?  I 
assume registration is optional and any two parties can opt to 
use it but all of our SERU uses so far have taken place between 
two registrants.

Sara Bahnmaier
University of Michigan Library
Associate Librarian and Head
Electronic Acquisitions & Licensing
320 Hatcher,
Ann Arbor MI 48109-1205