The question of whether to have your blog in a subdirectory on your site (yoursite.com/blog) or on a subdomain or microsite (blog.yoursite.com or yoursiteblog.com) comes up often. The quick answer for the best SEO is usually to have it in a subdirectory, though there are a few exceptions.

When to use a subdirectory:

  • If you have a site that isn’t updated very often, the fresh content on your blog brings search engines back regularly
  • If your site has high PageRank, TrustRank, and Domain Authority, your subdirectory inherits these rankings
  • If your blog is new, you’ll be verified and indexed by search engines more quickly and often on an established domain
  • If the content in your blog is closely related to the your site or industry, you strengthen your brand

Advantage: SYNERGY

  • Consolidating content and relevance in one spot, all links, tweets, likes, and other forms of sharing point to the same domain
  • Updates anywhere on site or blog keep content fresh and relevant for search engines
  • Your blog inherits the authority of your site so it can rank immediately for relevant search terms
  • One site architecture, one navigation scheme, and one design improve usability
  • Google Analytics reports are all in one spot

When to use a subdomain/microsite:

  • If the content on your blog is considerably different from that on your website and draws a different audience
  • If the content on your site doesn’t complement your brand and won’t help it rate for the search terms you want
  • If you want the blog to have a URL with a distinct brand and descriptive name separate from your site
  • If you plan on selling advertising on your blog and want to keep blog traffic data separate from site traffic data to attract advertisers
  • If you plan on selling your blog and the business associated with it
  • If your blog and site already both dominate search results and you appear twice at the top of search engine results with the two sites
  • If you have an eCommerce component to your blog or site and want to keep the two separate for security

Advantage: SEPARATION

  • You can more easily brand your blog separately
  • You can have a catchy, memorable domain name
  • You can keep analytics data separate from that of your site for advertisers or buyers
  • You can appear more than once in SERPs
  • You can improve security by keeping eCommerce functions on a separate server

Subdirectory vs. Subdomain Infographic: Click to enlarge, or download a PDF.

Your particular situation might warrant further consideration. If you already have a setup that’s working for you, you might want to leave it. You can ask a professional for advice, or read some of the links below to join in the discussion and learn more:

SEOmoz Whiteboard Friday – The Microsite Mistake

Root Domains, Subdomains vs. Subfolders and The Microsite Debate

Subdomains and SEO – Pros and Cons of Subdomains vs. Subdirectories