Much like Chrome and Safari, installing extensions on Opera adds little automatically updating buttons to the right of the search bar. Opera's extension gallery has just over 200 extensions at the time of writing, a small number compared to the number offered by either Firefox or Chrome, but it's a start. Tab stacking, meanwhile, is a feature that will prove useful to those who find themselves with a large numbers of tabs open on a regular basis. As its name implies, tab stacking enables you to group them by site or theme, similar to what Panorama does in Firefox 4. Stacking tabs is as simple as dragging one tab on top of another. To expand or contract the group, use the small arrow that appears next to the tab. Here's a video of the feature in action:
Opera 11 also has better mouse gestures with a new visual interface that highlights available mouse paths. The address field now hides unnecessary information and puts the security status of each page front and center. You might notice there's an improved auto-update system that makes sure that your Opera, its extensions, and Opera Unite apps are up to date. Last but not least, plug-ins like Flash can be set to load on-demand.