When you come to install a blog on your site using a blogging platform such as WordPress, you have two options. You can either install it on your website within a folder, such as yourdomain.com/news or you can host it on a subdomain, such as news.yourdomain.com.
The reason you might use a subdomain is if your website is hosted on a Windows server and you want to use a PHP blog, such as WordPress. This would mean you’d need PHP hosting on a separate server, hence the subdomain.
However, is a subdomain as good? Will Google treat your website and the blog as the same website, counting the pages together and the strength of the website as one site?
In truth it depends on the subdomain. Some are counted as the same website, some are not. For example blog.yourdomain.com is counted by Google as the same website. This means you can have a WordPress blog hosted on a subdomain without losing any SEO benefit.