Yes folks, that's right, according to a very recent status update, the original Twitter profile layout available when using Twitter's website for all your tweeting activities is going away. As of next week, the rest of the users that have not yet made the switch will be forced to move on from the old and into the new. Of course to most Twitter users, who hardly use anything but their smartphones or third party desktop applications like TweetDeck to do their tweeting, this will have no bearing on them.
The only thing you might want to think about is if you have a customized background graphic with your information on it that caters to the old layout, you will want to revisit it with the new layout since the new version's content areas spread out much wider and have different characteristics and a transparency thing going on.
So to that end, so long old Twitter layout. You've been kind and simple. Thanks for all the fish...errr fail whales.
For more information on the "New Twitter," check out the landing page for details.