Based on the recent changes to the website and iPhone app, here's the direction I see Twitter heading in 2012:

• Tweets older than five minutes are automatically deleted. It's all about real-time, baby!
• Twitter Search will go away completely. Yet another confusing feature, gone!
• Tweets without hashtags will be demoted. Hashtags are where it's at!
• Private messages will go away. Why would you talk to your friends when you can interact with companies?
• Your timeline will be filled with sponsored tweets (perfectly relevant to your interests, of course!)
• Companies can write tweets longer than 140 characters, and include images and videos right there on your timeline. Sweet!
• The star button will change to a "Like" button.
• You can comment on sponsored tweets, and tweets from hot celebrities like Kim Kardashian!
• No more permanent linking to tweets. Only those darned /power users/ and /journalists/ used this feature anyway.
• No more third-party clients. These *confuse* users!