Internal blogs refer to blogs within the organization that operate behind a firewall. Some organizations have only a single blog to update employees about the latest news and changes implemented. This is far easier to manage, control and ensure that the content adheres to the corporate policies. Some enterprises allow employees to form blogs and share their ideas, though such practices are harder to control. Blogs improve communication, increase knowledge and clear doubts instantly and hence are necessary tools.
External blogs are made available on the Internet and can be viewed by anyone. It helps you to communicate with your customer. If you have a voice, you don't appear to be a nameless and faceless corporate entity. Customers like dealing with people and a blog helps your customer feel like they are buying from a real person. It gives you a chance to share information and news with your customers. It's a great vehicle to drive information to your client base without pushing information at them too aggressively. They choose to read your blog and choose to find out about your company. They can also choose to comment and they can help spread the word. Blogs get syndicated and people do social bookmarking with them as well. Your blog is ideal for viral marketing!
Your blog should be optimized for your keywords just as much as your website is in order to attract the right audience. Blog posts should give value to readers and encourage participation. You can also use your corporate blog to announce contests, special discounts and to get feedback from your customer base. Besides that, it can drive traffic, get you more customers, increase customer satisfaction and improve your SEO rankings.
An example of corporate blogging is Google blog http://googleblog.blogspot.com. Google use its blog to make new announcements, get reviews about its products etc. It announced a push to get advertisers and publishers to utilize video ads. Google said they will sell both “InVideo” ads, where a video ad appears at the bottom of a video, as well as text overlay ads that put text below a video. The InVideo ads are paid on a CPM basis, while the text overlay ads are paid on a CPC basis.