BlogAssist has a handy command in the Services menu for all apps that support it. This command takes the selected text and any text in the clipboard, and displays them in a small window similar to the floating one. When you click OK, it applies the selected operation to the text and replaces the selection in your document. Very handy.
By default this command has the keyboard shortcut of Cmd-<, (i.e. Cmd-Shift-,) but you can change it via the System Preferences. Follow these simple steps:
Note: the new keyboard shortcut won't show up in applications that are already running until after you quit and re-launch them.