If you have a business website should your blog be on your main site or a separate website? In the past having a blog that was on a different domain benefited your main website because it provided multiple links to boost the ranking of the site. In fact, this became a commonly used SEO technique.
Unfortunately, because this could be used to manipulate the rankings of a website Google made changes to prevent this happening. Google wants internet users who enter a search to see the most relevant content and frowns on artificial link building that attempts to push a site to the top of the search results pages artificially.
Google now has algorithms in place that seek to identify website linking schemes and evaluates links to external sites in a different way. But it still continues to look favourably on fresh content and regular updates on a website because this makes a site more relevant (rather than out-dated). So, in short, a blog that is part of your main website can now make a positive contribution from an SEO point of view and is especially recommended if your website is hosted on WordPress.