How does an organisation decide whether or not to have its own blog? Here are some tips:
Can you update the blog several times a week?
Do you have a writer or group of writers who can support the blog?
Do you have something interesting to say other than just linking to other blogs and news sources?
Can you provide information of value to your readers?
Do you read other blogs and do you have an understanding of what is being talked about regarding your industry and services?
Do you have content on your web site (white papers, case studies etc) which you can link your blog to in order to take visitors further?