Because newsletter templates are available in all variety of lengths and sizes, there is really no limit to the content that you could potentially write. Keep in mind, however, that you should probably keep down your word count to a level that people are comfortable reading. While you may think everything that you are spouting off is fascinating, it's helpful to first sit down and make an outline of what you want your main message to be, or what the major news is that you are trying to share.
Article templates can also help you with your blogging. No matter where your writer's block is at a template of some sort will help you get through it one way or the other. You may look at the template and say, I can't write anything on that, but this one came to mind instead. Article templates are a great way to get yourself over a hump in your writing or they can help you come up with even more topics to write on. When you have writer's block you need to remember the traditional ways to come up with topics and then them about article templates.