Opera Link: Now lets you synchronize custom Search engines and typed History too. So any website address you typed in one computer will be available in all your other computers.
Feed Preview: Click on the feed icon and you will see it in a clean and efficient layout especially formatted for your window size. This makes it easier to see the feeds content before subscribing to it or even bookmarking it for quickly viewing what's new in a page without distractions.
Speed Enhancement: Go on, surf around, you'll notice the Web is snappier in Opera 9.6 with faster page loading than previous versions.
Low Bandwidth Mode: Now the mail client reduces data downloads as much as possible so you can check your mail faster when you are on the move. Enable it in your account properties and enjoy a faster email experience.
Follow Threads: Keep your eye on important discussions by right-clicking on one of the emails and selecting Follow Thread. All related emails will now appear under the Followed Thread view in your Mail panel.
Ignore Threads: Not really interested in the American Idol discussion your co-workers have going on? Just right-click on the email and select Ignore Thread. Past and future emails from this thread will now skip your unread view.
Full changelog at Opera.
Internet and communication
Windows, Linux, Mac
Product page: here