One MAJOR limitation that iWeb has is an annoying tendency to convert your text into image files! If those awful blog URLs dont scare off the search engines, they wont be able to read much of the content you spent all day writing.
A review of MacOSXhints.com tells you that the problem is related to iWeb having trouble with some font files that are installed with Office X and other applications, and by finding and disabling these fonts you might be able to get iWeb to knock it off. Overall the frustration was not worth it. If a font is called "Arial" and "Arial" is known to be in the web safe fonts list, then iWeb should not even try to render it on export, it should simple apply a style tag that says "font-family: Arial, sans-serif;" and let the browser work it out.