Q: Should we create our blog onsite or offsite?
Answer: If the purpose of your blog is for it to help your website with search engine optimization (SEO), then it is preferred that the blog resides on your main domain to achieve the best possible results. An offsite blog such as Blogger or Blogspot is easy to maintain, however, lacks the SEO value that an onsite blog delivers.
In addition, an onsite blog allows for customization that can enhance a reader's experience. The blog platforms available allow you to match the branding, functionality and characteristics of the rest of your site, so if a post is shared, your brand will be automatically recognized. Categories and tags can also be created to help your readers find related content quickly.
Once your onsite blog is created and launched, the new content has the immediate opportunity of being crawled and indexed. Search engines love fresh content; it allows your website to have a better chance at achieving higher rankings in the natural search results. An offsite blog on the other hand, would be seen as a separate website (which would have to be optimized and marketed as such) and any new content added would not be of value to your main site.