Google Analytics added a very valuable option: to add Annotations over the time graph. Annotations allows any user with access to a Google Analytics profile to leave shared or private notes right on the over-time graph. This is a simple note that will appear on the time graph on your main dashboard.You could use this feature:

• In case the servers went down?
• When did the new display ads campaign launch?
• Increase in your PPC budget
• New website launch
• Redesign of certain pages
• New product launch

This is a very useful feature especially within organisations with multiple departments. Annotations can become your central logbook, for all online marketing and website design actions within your business.