There are a lot of small companies that want an official blog or twitter account, with full control over the quality of the information published. We've seen a recent boost in automated systems that post prior-approved blogs/tweets. This is an operation that needs two functions: a "system that can post to a blog or twitter account by email" and a "workflow system that can send process data by email*." (Email is the key joint factor.)
* That is, a system that handles message throwing intermediate events (BPMN term), such as Questetra BPM Suite.
When designing a workflow like this, it's easy to become excessively focused on the end result (posting the blog/tweet), and neglect the point of initiation (writing the blog/tweet). In our workflow the marketing members are in charge of writing the posts, but what if nobody has anything to say? (If your company is full of motivated, verbal members, proceed no further.)
One idea is to add an upstream "Idea Memo" task for employees to send marketing members little news, like new functions or design changes in the company's product. Marketing members will most likely be grateful to be able to skip the step of fishing for stuff to write about. (You could also think about linking the workflow to your company's unofficial internal blog, if you have one.)
And in case you were wondering, this website (workflow-sample.net) uses a blogger system in which approved articles are automatically posted.