Blogs are an excellent marketing tool and are often picked up by Search Engines if they have useful or informative articles.
Most SaaS websites provide a blog page. This can be used to write articles or even update people on your latest news.
When writing a blog article always remember who are you writing for and what your audience cares about. Forums on your niche are very useful sources of information on what people are discussing and what trends are being followed. Do look at your competitors posts and particularly the comments and shares under those posts.