Blog posting is one of the best strategy to marketing your business online,its the part of off page SEO,its really very helpful to get traffic in your web site,it gives backlinks faster and helpful to increase the sales.
Both, blog posting and forum posting have their own benefits. The most important aspect is posting content that is relevant and that provides with value to the people. Only then you will be able to get a good response for a blog post or a forum post.