title: Multi-tenancy client-specific customization for SAAS
body: <p>Hi I have a question related to SAAS model and multi-tenancy.</p>
  
  <p>As far as I know SAAS multi-tenancy application means common functionality 
  for all clients, with some customizations of UI and functionality underNeath.</p>
  
  <p>If I need make for some customers additional client specific-customization , how I can achieve it?</p>
  
  <p>I know about approach of <a href="http://wiki.developerforce.com/page/Multi_Tenant_Architecture" rel="noreferrer">SalesForce</a></p>
  
  <p>As for answer I apreciate to see you experience with such 
   - customizations under database level,
   - architecture of backend in general or in 
   - any links for this topic. </p>