Answering Frequently Asked Questions, commenting on new industry developments or events that may impact your customers are great subject starters.
Not only do they demonstrate you are keeping up with new trends, but they can also portray you as an expert in your industry.
Another easy blog / v-blog or twitter subject may be to answer frequently asked questions from your customers.
The old FAQ section of a web site is long gone. With the new technologies that are emerging, the Internet has become truly interactive.