Quote - (halcyoncmdr @ Jan 18 2008, 12:50)

Opera does not support any sort of Toolbar API. However, there are ways to emulate the same features from those toolbars whithout having to install a separate toolbar. A simple edit of the existing toolbars can duplicate most of those features.
well, I always miss the "site rating" and "translate balloon" functionality of Google Toolbar, albeit I can live without them since Opera is better in almost all aspects except extensibility. I know it's quite easily to tweak the context menu and with a click it can show the site rating and phrase translation in a new tab, but it's just not convenient.
Sure a lot of functions can be emulated with a search, but the whole point of modern web browsers is to make things easier, to present information in a more accessible and user-friendly way, else we should just stick with tables and forms instead of css styling and ajax since they can provide most of the functions anyway.
Now with IE8's Activities and WebSlices, I surely hope Opera can open up a bit and provide at least some interfaces for extensibility and/or browser shells. Then it will be the greatest thing ever on Earth