The State of the Union livestream via WhiteHouse.gov is "enhanced," in that it'll likely carry social media updates and include charts and graphs that help the president to expound on his points to the audience. It's part of what may be the most "social" State of the Union address in history.
It could be a very effective method of communication. One of the difficulties of any speech is the fact that it's just a speech, there's nothing visual there. Using the power of online media to accentuate the spoken words could help to persuade more viewers of the president's points. Or not, we'll soon find out.