I collected all the public tweets containing 'Obama' during 2009. There were over 5 million recorded during the course of the year. I've done some analysis on a sample containing every 20th tweet. This first graph simply shows the distribution over the course of the year of the number of times the name 'Obama' was used. The curve has a big peak during the inauguration, a few smaller ones in February and March and is then remarkably level for the rest of the year.
This set of graphs shows other words that were used frequently in the tweets about Obama and that had distributions with a high concentration near specific dates during the year. When ordered by the peak date for each graph they give an interesting graphical narrative of Obama-related events during 2009.