by Larisa Thomason,
Senior Web Analyst,
Many large Web portals and online retailers structure their sites using subdomains. That structure helps organize diverse topics into a coherent format. Smaller sites use them to save money and boost site promotion efforts. Subdomains may even work for your site, but it's important to understand both the risks and benefits before you decide.
Organizing Topics With Subdomains
Most Web sites have a subdirectory structure. For instance, a cattery owner who breeds three types of purebred cats might structure her site to include a subdirectory for each breed:
But she has another option too - separate the site topics using subdomains. For instance, the owner of the Catting Around Cattery might want to create a subdomain for each individual breed of cat raised at the cattery. That gives her the opportunity to build and promote each as a complete online reference for each breed.
A subdomain lets you brand your different specialties with your primary domain name. With a subdomain, you can keep your well-known domain name, yet clearly indicate that each subdomain is a standalone resource.
Carefully Structure Your Subdomains
Each subdomain should be structured like a complete Web site. So in our cattery example, the subdomain MaineCoonCats.CattingAround.com should have its own home page that is specifically about the Maine Coon Cats bred at the Catting Around Cattery.
The other pages in the subdomain should be breed-specific as well.
- History of Maine Coons
- Articles about Maine Coons
- Care and feeding tips for Maine Coons
- Grooming hints for Maine Coons
- Available kittens at the cattery
Search engines consider subdomains to be independent Web sites even though they may share the same IP address. A shared IP address is common because so many Web sites use virtual hosting instead of running their own server. But do check with your Web host to make sure you're sharing and IP address with legitimate sites. Otherwise, something as basic as your choice of Web hosts could get your site banned from some search engines.
With a subdomain structure, site owners can legitimately submit each subdomain to search directories because each offers a specific focus and unique content.
Avoid Spamming Penalties
The term unique content is key here! Avoid a common mistake that can get your entire site either penalized as a spam site or banned entirely.
Some legitimate sites make the mistake of using duplicate content in their subdomains - but do it perfectly innocently. An example would be if the Catting Around Cattery used the same home page for each subdomain. The owner might assume that since the site is about the cattery and its cats, she should use the same introductory page for each subdomain.
That simple decision can get the site penalized or even banned entirely.
Any duplicate content sets off alarm bells at search engines, but they treat duplicate content in subdomains particularly harshly. Their suspicion is justified because subdomains have been so misused by spam sites. Here's what happens:
A spam site called something like "YouWinBettingCompany.com" sets up a variety of subdomains like this:
It looks innocent because each subdomain appears to focus on a particular sport. But in reality, the spam site has just copied the information from one subdomain to another. Then it links between the main site and each subdomain hoping to improve each section's link popularity score.
This strategy may work for a while (probably weeks instead of months), but you eventually get found out and then kicked out of search engines. It's not worth the risk!
When (And Why) To Use Subdomains
Used wisely, subdomains can help you organize your site, promote it, and even save some money on hosting fees!
- Cost savings. You may or may not save money, so don't get excited yet. Some Web hosts require you to purchase a separate hosting account for each subdomain. Look for a host who allows customers to set up multiple subdomains for no extra hosting costs. It's like getting several different Web sites for the price of one.
- Easier domain maintenance. With a single domain name, you only have one annual payment, login, and expiration date to remember. The same goes with your hosting account if your host allows multiple subdomains on the same account.
- Higher search engine rank. You get a boost in most search engine algorithms when you use your important keywords in your domain name. But if you're targeting ten or twelve, they're hard to cram into a single name. Subdomains give you more opportunity to include keywords with your domain.
- Maintain a consistent theme Most search engine ranking algorithms consider the site's overall theme, so you can have problems if one subdirectory is about cat grooming, another about home schooling, and the third about pizza ovens. Subdomains let you pull out each topic and create an entire site around that individual subject.
Site Maintenance Problems
This all sounds great, but carefully consider how much time you're willing to spend maintaining your site. Since you need to treat each subdomain as a separate Web site, need to store and maintain images and content separately.
Let's go back to the cattery example. Although the owner may use the same cattery logo, contact information, and basic information about the business, it needs to be saved separately in each subdomain. So each subdomain has its own image folder and Web pages with some of the same information. The owner has to remember to update all three subdomains each time some of the common information changes.
You can compensate for this somewhat by using server-side includes if your Web host allows them. Still, do understand that subdomains take more time to maintain. Make sure you're willing to expend the extra effort!
Content Is More Important Than Structure
Structure aside, you'll get the biggest site promotion boost by creating valuable content and consistently using important keywords throughout your site. You have many opportunities to include them in site content:
If you're having problems selecting the best keywords to target, use Search Engine Power Pack's Keyword Selection tool. It helps you evaluate the popularity of particular keywords and phrases and determine their value to your site. Then Page Primer (also part of Search Engine Power Pack) scans your page content and alerts you if you've used the keywords too often (which can get you banned as a spam site) or used them too little.
Are Subdomains Right For Your Site?
Basically, if you're thinking about subdomains primarily as a site promotion strategy, you need to think about something else. You can get the same benefits through conventional site promotion methods, without the danger of spamming.
And consider how subdomains might affect human visitors too.
Visitors aren't as familiar with the subdomain structure, so it's harder to remember a URL that uses it. Which would be easier for a visitor to remember if he saw it in a print advertisement?
Both are pretty long and hard to read even with capital letters in the domain name. Still, with a subdirectory, a visitor who forgets the subdirectory name but remembers the domain name can still navigate to the subdirectory from the home page.
Every site and every subdomain is different, so there's no single best way to organize a Web site. Changing to a subdomain structure may save you time, effort, and money. Or it could cost you a top search engine rank and make site maintenance a nightmare.
Consider the ramifications carefully before you make any drastic changes to your own site.