IE8 Activities look cool. They’re almost like favlets from where I stand, but they offer a very simple way for users to access online services and pass simple parameters.
I decided I wanted to play, and we use SharePoint heavily here at Black Marble. The obvious thing to do was to create an activity which would allow the user to search for the selected text using SharePoint search.
Activities are defined through XML. Essentially, you give it a name, an icon and define the actions that can be performed. There are execute and preview actions, but the small preview window doesn’t really lend itself to SharePoint search (I tried!).