In Moving blogs onto law firm website is misguided approach for large firm SEO, Kevin O'Keefe shares his experiences and advice on maintaining separate domains for your law firm website and your legal blog:

LexBlog is getting inquires from large law firms asking if it would be worthwhile to move their blogs from being independent sites onto their law firm website. The question appears to be driven by the desire for search engine performance.

The firm or someone advising the firm believes by moving independent blogs onto the firm's website, the search engine performance of the website would be improved. Based on how well large law firm blogs are performing on Google that sure seems terribly misguided.

While Kevin provides examples of separate domain legal blogs that have excellent search engine positions, the decision as to whether to blog on a separate domain vs. a subdirectory vs. a subdomain of your law firm's primary domain isn't a one-size-fits-all proposition. In fact, depending on your specific web strategy, each of these strategies may make the most sense.

URL Gobbledygook

Before we talk about some of factors in play in choosing between a subdomain, subdirectory, and microsite, it's helpful to understand what each of these parts of a URL are.

As Google's Matt Cutts explains:

Historically, it’s been kind of a wash about when to use subdomains vs. subdirectories. Just as a reminder, in a URL such as subdomain.example.com/subdirectory/ , the subdomain is “subdomain” and the subdirectory is “subdirectory” (also sometimes called a folder). If you’re still unclear, you may want to read my tutorial on the parts of a URL.

Further, a microsite strategy involves selecting an entirely new domain upon which to launch your blog. Using the above example, if you have a website www.example.com, implementing a microsite would mean registering and launching www.example2.com.

An SEO Perspective

The debate regarding subdomains, subdirectories, and microsites is not a new one. Discussions on these topics date back at least to 2006 if not further. However, there was a significant change with Google that might have an impact on your decision.

In Root Domains, Subdomains vs. Subfolders and The Microsite Debate, SEO ninja Rand Fishkin provides some helpful advice:

Search engines have metrics that they apply to pages, such as PageRank, and metrics they apply to subdomains and root domains (including things like TrustRank, various quality scores, domain level link metrics like Domain mozRank, etc.). Through years of experience, observation and testing, SEOs have observed some very steady patterns of behavior:

Individual pages benefit from being on powerful subdomains & root domains. This is why if someone copies your personal blog post on the best way to microwave burritos into Wikipedia, that page will rank far better than yours, even with the exact same content (ignoring the duplicate content issues).

Subdomains DO NOT always inherit all of the positive metrics and ranking ability of other subdomains on a given root domain.

Some subdomains GET NO BENEFIT from the root domain they're on. These include sites like WordPress.com, Blogspot.com, Typepad.com, and many others where anyone can create their own subdomain to begin publishing.

Subfolders DO appear to receive all the benefits of the subdomain they're on and content/pages behave remarkably similarly no matter what subfolder under a given subdomain they're put in.

Good internal and cross linking CAN HELP to give share the positive metrics from one subdomain to another (but not always and not perfectly).

For these reasons, if you're seeking to maximize your ranking ability for a given piece of content, it's my personal belief that you should, most of the time, keep it on 1 subdomain under 1 root domain (but feel free to use subfolders as it makes sense). Starting a blog? I almost always recommend yoursite.com/blog over blog.yoursite.com. Want to launch a new section of content? Use yoursite.com/newstuff rather than newstuff.yoursite.com.

However, there are exceptions...

Generally speaking, from an SEO standpoint alone, subdirectories are GENERALLY the optimal choice. However, as stated at the outset, they aren't always the best choice in all situations. For example, if you have an established authoritative law firm website, your blog is likely to gain ground in search engines in a shorter period of time. Further, links acquired to your blog will provide "link juice" to your firm's root domain which is likely to help your law firm website gain ground in search engines too.

This is why having someone that has a full understanding of your web strategy and goals can be very helpful in making choices about starting a new practice-specific microsite or legal blog.

Finally, this post discussed the domain decision primarily from the search engine perspective. There are several other factors that may play a role in making a decision about where to blog. For instance, branding decisions should also play a large role in your web strategy.

In the end, each legal blogger should make an informed decision about where to blog that fits within a comprehensive web strategy.