From: http://virtuelvis.com/archives/2006/02/opera-9-tp-2
Opera 9, Technology Preview 2 has just been released. With changes. Read on and get the meat of the story: Widgets, thumbnails, BitTorrent and more.
Widgets
Yes, Opera 9 now features Widgets: Small web applications that run outside the browser, directly on the user’s desktop. These widgets, unlike a regular browser, has cross-domain features, so it’s an ideal platform for delivering Web applications that interact with multiple online services at once. Opera Widgets are cross-platform, and run both on Windows, Linux and OS X.
Since widgets are chromeless, they’re also ideal for eye-candy applications, such as this analog clock:

If you are a developer, and would like to get started with widget development, see the Widget developer’s page — the tutorials there are:
Over time, more documentation for developers is going to be added to this page, from the simple to the more complex.
With widgets, Opera is also introducing OWAL, the Opera Web Applications License 1.0 which allows authors to reuse libraries developed by Opera for widget development.
Content blocking
Opera has always had the opportunity to block unwanted external content. Up until now, this has been an expert-only feature, requiring editing of the urlfilter.ini file. Well, those days are long gone. You can now right-click on any page, and select “Block content” to block external images, flash movies:

If you want to see more of the content blocker, my colleague Petter Nilsen has written in-depth about it, with multiple screenshots.
BitTorrent
Yes, BitTorrent is back. This is technology previously previewed in the 8.10 cycle, then it went away for a few versions. The client has improved since then, in addition to bittorrent search being added. Use b [search term] in the address bar to search files directly on search.bittorrent.com
opera:config improvements
opera:config, introduced in Opera 9 TP1, has seen some major improvements, style-wise:

Not only is the styling improved, the functionality is also improved, as every item in the file now has a permalink, signified by the »
after an item, so pointing users to the exact setting you’re refering to is as easy as creating any other link on the web.
Web page thumbnails
Opera 9 tp2 features Web page thumbnails when you hover over tabs:

Not only are these thumbnails in the tabs, but they are also added as an option to the Ctrl-Tab cycle:

The Ctrl-Tab is turned off by default, but can be turned on by checking the option Use Thumbnails in Window Cycle in opera:config
Again, you can view more screenshots over at Petter Nilsen’s blog.
History

The history panel and history tab in Opera has seen some major improvements in this version: The history is no longer a flat list of items you have visited. Instead you now have these views:
- Time and site view: This view groups your site into “Today”, “Yesterday” and similar, with the domains you’ve visited grouped as subfolders inside this view.
- Time view: This view groups your history by date, and keeps the sites visited on that date in order, with no other particular grouping.
- Site view: Like you probably already guessed, this simply organizes your history by domain.
Error console
The error console in this preview is pretty much all new. First of all, it’s now renamed from “JavaScript console” to error console, because it now is host to all of the error messages in Opera: M2, Java, JavaScript, CSS, XML, XSLT, SVG, Network, and BitTorrent errors.
Source viewer
The source viewer/editor, introduced with TP1 has seen further improvement, as it now also syntax highlights source

Customizable searches
The searches in Opera are now customizable from the Search tab in (the improved) Preferences:

Again, Petter has more details on search customization
Site-specific preferences
If you need to customize aspects of a site, like change its plug-in settings, alter the appearance by pointing to a different stylesheet, changing cookie settings or similar, Opera now has site-specific preferences:

Access to the site-specific preferences is through an extra menu item in “Quick preferences” (F12) which will open a dialog with the preferences for the site you’re currently visiting.
labs.opera.com
In conjunction with the release of this preview, the new Opera Labs site is also set to go live. Bookmark it, visit it, and subscribe to the RSS feed.
Much more: Changelogs
There really is much more, but if I was going to delve into it all, this would end up as the longest blog post in history. I’d suggest checking out the changelogs, where you’ll also find the appropriate changelogs:
In addition to these, you can read some other Opera employee postings on Opera 9 tp 2 (This list is live):
You’ll find the appropriate download links in the changelogs. Remember: This is a technical preview, not production software. Which means that we appreciate bug reports and feedback, which you can do by filing bugs, and/or posting in the Beta testing forum.