You can learn alot about Corporate Blogging from hardcore music groupies. They are the ones who have been with you since the start, saw you play at your first concert, have all your cd's and have shrine to you in their bedroom.
Writing a corporate blog will no doubt start with a low level of traffic coming to your blog. This may make you skeptical of the power of blogging and whether you are just wasting your time. However this small audience (groupies in the making) will be the most valuable to your company.
The first few reader to your blog will invariably be your brand fanatics. These are the people who want to go out and source new information about your brand. These are the people who speak about your brand to all their friends and swear by your products. As like my previous example of AC/DC and corporate blogs your first fans with be your dedicated groupies who are passionate about the music.
Embrace these people.