Constituents, Constituents, Constituents!
Relational DB with constituent table at the core.
Ability to manage LARGE lists/groups of constituents. (Approx 50,000 - ??? 1,000,000+???)
CMS system - 
    Templates
    Easy to modify 
    Standard content types (graphics, text, etc)
Publishing engine
    Export to Facebook, Twitter, Myspace... unified, cross site presence
    Metatag to ID content
    DKIM authentication of content
    ImagePortal / image server, rights and protection validation of content license
***Museum Centric
Artwork follow up.  
Web page connect. 
TMS tombstone info.
Allow public voting / curation of exhibition based on links.
NetFlix like recommendation system?  If you liked this work, check out THIS one!
Commercialize?  Put reproducable image(s) on mugs, calendars, coffee cups, skateboard decks, etc?