As of last night, selected Twitter users will be able to embed videos in their tweets, along with a series of other new features. Plans are to expand the upgrades system wide in the next few weeks.
The Twitter company blog has more details:
New design. The site has a cleaner timeline and a rich details pane that instantly adds more impact to individual Tweets while still maintaining the simplicity of the timeline. And, experience infinite scroll — you no longer have to click “more” to view additional Tweets. Media. Now, it’s easy to see embedded photos and videos directly on Twitter, thanks to partnerships with DailyBooth, DeviantART, Etsy, Flickr, Justin.TV, Kickstarter, Kiva, Photozou, Plixi, Twitgoo, TwitPic, TwitVid, USTREAM, Vimeo, yfrog, and YouTube. Related content. When you click a Tweet, the details pane shows additional information related to the author or subject. Depending on the Tweet’s content, you may see: replies, other Tweets by that user, a map of where a geotagged Tweet was sent from, and more. Mini profiles. Click a username to see a mini profile without navigating from the page, which provides quick access to account information, including bio and recent Tweets.