Spring '12 Features that need to contact Salesforce.com to enable the features

• Chatter Messenger
• Chatter Answers
• Live Agent
• Console push notifications
• Knowledge Actions(Pilot)
• Introducing Analytics Edition
  
  1. Joined Reports—Generally Available
  2. Cross Filters—Generally Available
  3. Data Bucketing—Generally Available
• Data.com Corporate
• Data.com Clean - Beta
• Single View State
• Repeater and Data Table Pagination(Pilot)
• Encrypted Fields Available in Full-Copy Sandbox
• Paging Using the OFFSET Clause

Cheers!!!