What is Butler? A file launcher. You can access applications and any other kind of document by browsing fully customizable system-wide spring-loaded menus, pressing hot keys, clicking hot corners, or entering abbreviations.
Butler will learn from your habits and remember what you want a certain abbreviation to do (e.g., enter "abo" to launch "Address Book"). Butler offers you a way to manage your bookmarks without depending on a certain browser. In contrary to a browser's bookmark collection, Butler's bookmarks are always accessible through its system-wide menus, hot keys, etc. And you'll certainly become addicted to accessing bookmarks by entering abbreviations. Butler also lets you access the bookmarks of every single browser there is for Mac OS X.
Adding files or URLs from your browser to Butler's configuration is stunningly easy: Just drag them to the active screen corner (default: top left), see Butler's main window open, and drop your items somewhere whithin your configuration. Butler's predecessor "Another Launcher" was the first application that let you search the web from the menu bar. But if your menu bar is too crowded for an input field, you can also use hot keys to pop up dedicated web search windows. Butler supports a large number of search engines by default, but you are not restricted to those ? you can easily add your own search engines.
Butler lets you access items you have previously stored in your pasteboard, effectively turning your pasteboard into a stack. You can also take a snapshot of your current pasteboard and keep it for good. This feature is particularly useful for text snippets you need to enter on a regular basis. You can use Butler to move and copy files, control iTunes, access the system preferences, change the current user, and so on. But Butler really shines when it comes to customizing its behavior. Is your menu bar too crowded? Use Butler's docklet. Do you want a menu for each mounted volume? Do you want a menu to pop up when you press a certain hot key? Do you want all running applications in your menu bar? Or do you prefer doing things with your keyboard only? Whatever kind of interface you prefer, Butler is at your service.