I recently spoke to the folks at Typepad about building a corporate blog. The details of the article are here: http://www.typepad.com/business/case-study-photobucket.html.
My advice for other corporate bloggers is summarized as follows:
Don’t commit to anything you’re not prepared to follow through on. To build trust, you have to be consistent. If you start a blog category called “What’s New” – but then you only update it every six months – you’ll lose your credibility.
Make sure people can find your blog; link to it from your main site. Most importantly, make your content useful and informative. If it’s just more ‘marketing speak’ it will just become background noise. Make a commitment to it, and allow someone in your company to run with it.