If your answer to this question is no, perhaps you should take a look at the website for Hill| Holiday. For those of you outside of Boston, Hill | Holliday is a PR/marketing firm with clients that include the Museum of Fine Arts in Boston, Chili's, AOL, Anheuser Busch, and Dunkin' Donuts.
The home page of the Hill| Holiday website is a blog. You can even scroll down to the bottom of the page and see the "proudly powered by WordPress" designation. They even have comments activated.
Is your marketing group still unsure about whether blogs are useful? The biggest marketing firm in Boston thinks a blog is a useful marketing tools for themselves. Does you marketing group know something that Hill| Holiday does not know?
Thanks to Stewart Mader at WikiPatterns for pointing this out in his Random Things he reading this weekend post.