In commenting on President Obama's speech to Congress last night, as is my wont, I will not try to settle the dispute between John Hinderaker (it was ineffective), Paul Mirengoff (the oratory was too effective for anyone's own good), and Andrew Sullivan ("the politics and rhetoric are superb").
But it seems like a good opportunity for me to discuss the implementation of the provision of Article II, Section 3 of the Constitution that requires the president to "from time to time give to the Congress Information on the State of the Union, and recommend to their Consideration such Measures as he shall judge necessary and expedient".
The constitutional parameters are vague, but custom and practice have turned that into an annual message, delivered as often as not in written form. The presidents from Jefferson to Taft took the written approach. Woodrow Wilson then revived the practice of making a speech in person to a joint session of Congress, setting a precedent that has been followed in most of the years since 1913.
The address has both retrospective and prospective elements. That is, it both describes the current state of things, and proposes future policies. In a presidential transition year, the outgoing president is best suited to provide the former, while it makes most sense for the incoming president to do the latter.
Here is a history of state of the union addresses, from The American Presidency Project at UCSB. That document indicates that outgoing presidents have considered it to be optional as to whether or not they give an oral or written address in their final year. According to that history, recent presidents, including George W. Bush, have done neither.
Incoming presidents often address Congress early in their presidencies, in speeches that take the same form as state of the union addresses, but are not called that.
John Kennedy made such a speech, 10 days after his inauguration. After he had settled in, and got off to a rocky start, he made a sort of second state of the union speech on May 25, 1961. It was then that Kennedy proposed the Apollo man-on-the-moon program.
Obama has followed the lead of more recent predecessors, addressing Congress after some weeks in the White House, mainly on economic issues.