Firefox, IE, Opera, and Konqueror have all agreed to a set of standardized security features that will find their way into all browsers in future releases. This is pretty significant. Throughout the history of web browser development, it's been near-impossible to get the various camps to agree on standards of any kind.
Some of the highlights of the agreed-upon security features include:
In the default setting, all pop-up browser windows will now have URL location bars, so that you can see what site is hosting the pop-up.
Beefed-up and phisher-resistant high security certificates will be created and issued to deserving sites. The notification will be standardized -- if you're on a site with one of these certificates enabled, your address bar will turn green.
I wonder how this will affect web developers who use sleek pop-up windows without location bars purely because they look better that way. It will be interesting to see if this practice phases out or if it sticks around on sites that don't have much concern with the perception of high level security.