If you paste content from Microsoft Word (or any formatted content) directly into the editing area of the WordPress backend, chances are a bunch of formatting code will come with it. Best bet is to use the little “clipboard T” (for plain text, recommended) or if you do have some formatting you’d like to try to keep, use the “clipboard W” (for pasting from Word). Both are located on the second formatting button bar. If you don’t see that button bar, click the icon/button on the right of the top row of icons “Show/hide Kitchen Sink.”
Here’s the video that walks through cleaning up formatting if you do paste in without using the clipboard icons.
February 2010 updated video
If you paste from Microsoft Word directly into WordPress without using the “Paste from Word” button, you’ll usually have some formatting issues. In this case, although the font seemed OK, the browser couldn’t read some of the “fancy quotes” or em dashes and turned them into vertical bars of codey-gobbledy-gook. Here’s how to manually clean it up and get rid of that nasty Word code.