Among the features are user-interface changes, tab messages using KMessageWidget, improved drag-and-drop, revamped SSL UIs, optional "vi style navigation", improved history support, Do-Not-Track support, KParts for viewing page source-code, a custom URL bar context menu, and other changes.
The Rekonq 0.8 changes are talked about in this blog entry. Additionally, the blog post ends with, "And if you like this release, you’ll be astonished from the incredible new features we are preparing for the next rekonq! Stay tuned."
For those unfamiliar with Rekonq, it's a WebKit-powered KDE web-browser that's lightweight and generally works much better than Konqueror (at least from my testing and the reports of others). If you prefer Rekonq to the more popular web-browsers like Firefox, Chrome/Chromium, and Opera, share your thoughts on this new release within the forums.
In related news, today marks the 15th birthday of KDE. Happy birthday, KDE!