The days are numbered for Twitter's old site.
The popular microblogging site announced today that it will migrate users still using the old home page to the new interface design this week.
"If you're currently using Old Twitter, we want to let you know that you'll be upgraded to New Twitter this week," the company said in its official Twitter feed.
Last September, Twitter began rolling out a complete redesign of its home page that provides users with a second viewing pane for different kinds of content, such as photos and videos, user profiles, and geolocation information. The idea was to make the home page more valuable by allowing users to maintain contact with their timeline of tweets on the left while viewing other content on the right.
As part of the redesign, Twitter struck deals with 16 media companies--including Flickr, YouTube, Vimeo, TwitPic, and others--that allow content from those services to display in the new viewing pane.