Twitter announced yesterday the launch of a major redesign in profiles and layout.
"Today we introduce a new version of Twitter. We’ve simplified the design to make it easier than ever to follow what you care about, connect with others and discover something new. You’ll see this new design both on Twitter.com and mobile phones, so that you’ll have a familiar experience any time, anywhere (...) Four new tabs bring you instantly closer to everything you care about."
We’ll be rolling out the redesigned Twitter over the next few weeks. You can see it immediately on the just-updated versions of mobile.twitter.com, Twitter for iPhone, and Twitter for Android. You can get early access on your computer by downloading and logging into Twitter for iPhone or Twitter for Android. We’re working on updates for other apps, such as Twitter for iPad, and will share news as they become available.
What we’re announcing today is just the beginning. We now have a framework in place that we will quickly build and iterate upon to help users connect with whatever is meaningful to them.
Source: Twitter blog
More information here: http://fly.twitter.com/index_en.html