The web version of Twitter is currently undergoing some sizable changes, which principally involves making it look like one of the many apps that have been developed for the service. Some people will already have seen these changes, while others are still waiting—you can check this Gizmodo post for a full rundown of what to expect.
Twitter has also produced this commercial (above) to help ring in the changes, and have used New York indie rockers Freelance Whales to provide the soundtrack. Embedded media, more information and deeper context are all promised with the new Twitter—so anyone enjoying its uncluttered interface may not be happy. Perhaps someone will invent an app that strips away all this additional content?