When you are developing a web site and want to use a custom font, via font-face, you might find that IE on Windows Phone refuses to use it. Turns out that IIS doesn’t include the mime-type by default so you need to add it. If you don’t have access to the site directly (maybe Azure web site or a shared server) you can add it in your site’s web.config webserver section;

<system.webServer>
    <staticContent>
      <mimeMap fileExtension=".woff" mimeType="application/x-font-woff" />
    </staticContent>
</system.webServer>