Although sub-directories appear to be more commonly used in developing sections of web sites, using sub-domains can give you an advantage in achieving a strong online presence. And while the advantage may be slight, every advantage works to your favor when your goal is to improve your search engine rankings.
You can recognize sub-domains and sub-directories easily. A URL for a sub-domain contains the name of the new section before the primary domain name, separated by a dot and replacing the www, as in http://finance.yahoo.com. In this case, ‘finance’ is a sub-domain of Yahoo.com.
A sub-directory contains another layer after the primary domain name separated by a forward slash, like this: http://www.sbdpro.com/blog. Here, ‘blog’ is the sub-directory of sbdpro.com.
You’ll find that using sub-domains rather than sub-directories lets you enjoy many of the benefits of primary domains, without having to find, register and pay for separate domains.
How Sub-Domains Can Boost Your Site’s Online Performance
· Search engine preference
The URL of a sub-domain may gain favorable treatment over that of a sub-directory, since sub-domains are treated as top level, unique sites, while sub-directories simply another level to a site.
Because sub-directories create another level, the pages within them are removed further from the main index or home page. Search engines generally don’t index pages that are more than two levels or two clicks away from the home page. Even if they do, the pages are not likely to reach significant ranking value.
Sub-domains offer the advantage of eliminating one layer. So the pages that are contained in your sub-domain are kept at a higher level than they would be in a sub-directory – and are therefore more likely to be indexed in search engines.
Since search engines usually view sub domains as unique from the main site, you can submit each sub-domain URL separately to search engines – as long as each sub-domain contains content that is appropriately unique for a separate site.
Using the keyword in the URL may provide slightly more relevance in the eyes of the search engine spiders. Sub-domains allow you to use important keywords directly in your domain name while keeping the URL short and memorable. While some companies may prefer to develop a separate primary domain, it can be difficult to find a suitable primary domain, so implementing keywords into your sub-domain names provides a means to access the same benefits.
· Submission in directories
Although many major directories like Yahoo and the Open Directory Project refuse submission of more than one domain from a company, they may accept multiple listings of URLs containing sub-domains, when the content of the sub-domain is unique from the main company site. In other words, major directories may treat sub-domains as unique URLs but sub-directories as simply more pages in the main site.
· The human click factor
When you’ve obtained the rankings and it comes down to getting searchers to click through, a URL that appears relevant to searchers can be more persuasive in winning the click from a URL that doesn’t contain the keyword. (Remember that people’s eyes move from left to right when reading, so including the keyword earlier in the URL is a benefit.)
· When Sub-Domains Should be Your Choice
The choice between sub-domains and sub-directories enters the picture when you have a significant amount of content to dedicate parts of your website to different products or company divisions. Rather than building a site that contains deep levels of sub-directories, you can create a more targeted top-level URL with sub-domains.
Following are some examples of situations in which sub-domains may be used instead of sub-directories.
· Presenting Product Lines Separately
Sub-domains can provide leverage over using sub-directories to distinguish among your products or company divisions. Sub-domains allow an organization to present product or service information separate from main corporate information but still retain the brand association.
This is especially useful when there is extensive information for each product line. Consider the case of Xerox.
A sub-domain separates their range of office products from their ancillary services. At http://www.office.xerox.com/ you will find tons of resources for their faxes, printers, and copiers. However, information on supplies and consulting are contained in sub-directories. Both the sub-directories and sub-domain are linked from the home page, but by placing the products in a sub-domain, Xerox’s key products enjoy a strategic advantage by maintaining top-level treatment of the targeted URL.
The sub-domain sections of the site can be developed as if they are an independent site, with plenty of pages that are distinct from the primary site. AAA maintains a sub-domain for its travel services, which are separate from its most well-known services for roadside assistance: http://travel.aaa.com/ . National Geographic also places its e-commerce capabilities on the top-level with a sub-domain: http://shop.nationalgeographic.com/
http://antiques.ebay.com/ and https://adwords.google.com are more examples of web-savvy companies taking advantage of the benefits of sub-domains to present a specific product category.
· Separating Company Divisions
A sub domain can give the appearance of being an independent web site, although it remains under your top-level domain. So when you need to reach different audiences, a sub-domain lets you segregate your web-site at the top level.
Consider the example of Ikea, which sells through retail franchise outlets. Potential franchisors can learn more about the business opportunity at the sub-domain http://franchisor.ikea.com/, since a company needs to communicate with consumers and franchisors separately.
Here you’ll find the official home page of the Walt Disney Company: http://disney.go.com. But in this sub-domain you’ll find all the information you need about the Disney resorts and parks: http://disneyworld.disney.go.com
You may notice that some large companies use completely separate domains for presenting information. Take General Electric for example: www.geindustrial.com/, www.gehealthcare.com , www.gepower.com, www.geappliances.com, etc. But you may find it more efficient to use sub-domains, which don’t incur the costs of maintaining separate web sites yet let you present divisions of your company separately.
· Appealing to Different Geographical / Language Audiences
By using sub-domains for the geographical areas where you do business, you can feature the keyword in the URL and develop culture-specific content. This is especially useful if you offer services across many regions. Siemens uses this approach http://usa.siemens.com and so does Kimberly Clarke for some web sites in foreign countries: http://www.kr.depend.com.
Many large companies choose to develop country- or region-specific primary domains, such as http://www.mitsubishicars.ca. However, there can be regulations pertaining to the foreign country code extensions that may be prohibitive. For example, some countries require the business to be based in that country in order to qualify to use the country code extension. Using a sub-domain for the country can be an ideal solution.
Sub-domains also allow you to offer content according to language. This can be especially appropriate if the foreign-language audience you want to appeal to is in your home country, such as Canadian companies offering content in the country’s two official languages of French and English.
· Creating Tracking URLs
Sub-domains can also be used to track traffic coming from online advertising media such as pay-per-click ads, banner or print advertising, or even affiliates. Using a separate sub-domain for each landing page lets you isolate web stats for each source. However, remember to keep sub-domain content targeted to the audience and different from the main site, as providing identical content in different sites is frowned upon by major search engines and can result in penalties.
Tips to Keep in Mind When Using Sub Domains
Some web hosting programs do not support sub-domains, so make sure yours does before trying to set them up. There may be extra charges for setting up and maintaining sub-domains. Your web site stats will not include your sub-domain stats, but you can view them separately. Be aware that your hosting service may call sub-domains by a different name, with some of the more common ones being “vanity names”, “machine names”, or “domain alias”.
