トップレベルドメインとは何ですか?
A top-level domain (TLD) is the last set of text in a domain name. For example, .com, .net, and .org.
The top-level domain provides additional information about the domain name. For example, .com indicates the domain is a commercial site, .net indicates it is a network, and .org indicates it is an organization. Similarly, .uk indicates the domain is targeted at an audience based in the UK.
Types of Top-Level Domains
The Internet Corporation for Assigned Names and Numbers (ICANN) is responsible for creating and assigning top-level domains. It currently categorizes top-level domains into six categories, including:
- Generic top-level domains (gTLDs)
- Country code top-level domains (ccTLDs)
- Sponsored top-level domains (sTLDs)
- Infrastructure top-level domains (ARPA)
- Generic-restricted top-level domains
- Test top-level domains (tTLD)
However, other classification systems may list some extra categories, including:
- Test top-level domains (tTLD)
- New generic top-level domains (New gTLDs)
- Internationalized country code top-level domains (IDN ccTLDs)
We will now explain them all below.
1 Generic Top-Level Domains (gTLDs)
These are the traditional top-level domains. They are open to everyone, irrespective of the type of business or organization they operate or the type of content they publish on their site. Examples include .com, .net, and .org.
2 Country Code Top-Level Domains (ccTLDs)
These are top-level domains that are specific to certain countries or territories. Country code top-level domains usually consist of two letters based on the International Organization for Standardization (ISO) country code. For example, .uk (United Kingdom), .de (Germany), .jp (Japan), and .in (India).
3 Sponsored Top-Level Domains (sTLDs)
These are specialized top-level domains sponsored by government agencies or private organizations. Examples include .gov (U.S. government entities), .edu (educational institutions), .mil (U.S. military), and .int (international organizations).
4 Infrastructure Top-Level Domain (ARPA)
This top-level domain is exclusively used for technical infrastructure purposes. It contains only one top-level domain, which is .arpa (Address and Routing Parameter Area).
5 Generic-Restricted Top-Level Domains
These are generic top-level domains. However, users are expected to meet certain requirements before they can own one. The three restricted generic top-level domains are .name (for individuals), .pro (for professionals), and .biz (for businesses).
6 Test Top-Level Domains (tTLD)
This refers to top-level domains reserved for testing purposes. They are not assigned to anyone and are not open for sale.
7 New Generic Top-Level Domains (New gTLDs)
Some bloggers use this term to differentiate between traditional generic domains like .com, .net, and .org and the newer generic top-level domains that followed. ICANN, however, recognizes them as generic top-level domains. Examples include .tech, .store, .blog, .xyz, .spa and .space.
8 Internationalized Country Code Top-Level Domains (IDN ccTLDs)
Some bloggers use this term to refer to country code top-level domains written in non-Latin scripts. For example, .рф (Russia), .中国 (China), and .السعودية (Saudi Arabia). ICANN recognizes these as country code top-level domains.
9 Brand Top-Level Domains (Brand TLDs)
Some bloggers use this term to refer to top-level domains owned by private brands or companies. The domains typically contain the name of the business or product. Examples include .google, .apple, and .microsoft. ICANN recognizes them as generic top-level domains.
How to Select an Ideal Top-Level Domain
Selecting a top-level domain is usually not straightforward. In many cases, the one you want may not be available, or you may be confused about which one to pick since there are just so many of them. These guidelines will help you reach a decision.
1 Consider Your Target Audience
A generic top-level domain like .com, .net, or .org is usually the best choice if you are targeting a worldwide audience. These are recognized and trusted worldwide.
However, if your target audience resides in a specific country, you should consider a country code top-level domain like .uk for the United Kingdom or .ca for Canada. Google has confirmed that these country code top-level domains will provide you with additional SEO benefits.
2 Select One That Fits Your Brand
Visitors associate certain top-level domains with certain industries or businesses. For example, visitors expect a .tech top-level domain to lead to a tech site. Similarly, they expect .tv to lead to a site belonging to a television station or program and .plumbing to lead to a plumbing business or blog.
However, you should know that these top-level domains do not provide you with any additional SEO benefits. They only help you fit into your user’s expectations.
3 Select a Trustworthy Top-Level Domain
Visitors may be critical of certain top-level domains, especially when they are not very common or are associated with spam. Google has also confirmed that it may refuse to 索引 sites that use top-level domains that are common among spammers.
So, before you pick up that not-so-common top-level domain, run a quick search to see the type of sites that use it. It may also help you understand how others view that top-level domain. That way, you can be sure you are selecting a trustworthy and spam-free top-level domain.
4 Consider Potential Legal and Trademark Issues
Not all top-level domains are open to the public. Some also have certain requirements you are expected to meet before you can register for them.
For example, certain top-level domains like .gov, .edu, .mil, and .pro have restrictions and can only be used by certain entities. Others like .google, .apple, and .airbus are owned by private businesses and are likely not open to the public. Then, a top-level domain like .eu is only open to European Union citizens.
SEO Implications of Top-Level Domains
Google has provided some information and guidelines on how your domain name affects your SEO efforts. If you run a site or are looking to create one in the future, it is crucial that you are aware of these guidelines and understand how they affect your SEO.
1 Country Top-Level Domains Give You a Little Boost
Google has confirmed that some country code top-level domains (ccTLDs) provide their sites with certain SEO benefits. So, if your target audience resides within a particular country, it may be helpful to use that country’s top-level domain.
For example, if your target audience resides in Germany, it will help to use something like yourdomain.de. Similarly, you can use yourdomain.cn if they reside in China or yourdomain.ru if they reside in Russia.
However, Google added that there are exceptions to this. Specifically, Google mentioned that it considers how people use a top-level domain before deciding whether to treat it as generic or as a country code.
If people use a country code top-level domain as generic, then we should expect Google to treat it as generic. For example, Google treats country code top-level domains like .ai (for Anguilla), .tv (for Tuvalu), and .co (for Colombia) as generic domains.
That said, Google has hinted that it will reduce the SEO benefits of country code top-level domains in the future.
2 City and Regional Top-Level Domains Are Generic
City and regional top-level domains have become quite popular lately. For example, .berlin, .london, .eu, .asia, and .africa.
Google has confirmed that it treats these top-level domains as generic by default. So, they are not very helpful for geotargeting and will not provide you with any additional SEO benefits, even if your target audience resides within those regions.
3 Avoid Cheap or Free Top-Level Domains
Google recommends that you avoid free or super cheap top-level domains. Spammers commonly use these domains to engage in practices that violate Google Search Essentials guidelines.
Google may refuse to crawl or index sites with these top-level domains, even if they do not contain spam and publish helpful content that does not violate its guidelines. So, it is best to stay away from them.
4 Keyword-Rich Top-Level Domains Are Not Helpful
Many bloggers wonder whether keyword-rich top-level domains like .jobs and .plumbing have any SEO benefits for sites that use them. For example, will a job listing site rank higher on search results pages because it uses a .jobs top-level domain?
グーグル has confirmed that such top-level domain names do not offer any benefits. So, a job listing site called yourdomain.jobs does not have any SEO benefits over another one named yourdomain.com.
5 .edu and .gov Top-Level Domains Do Not Offer Any SEO Benefit
Many SEOs and bloggers believe that sites with .edu and .gov top-level domains always rank highly on Google. Google, however, refuted those claims and said they do not provide any additional SEO benefits.
6 Older Top-Level Domains Are No Better Than the Newer Ones
There are many top-level domains around today. This has raised concerns among bloggers who think they may have issues if they use the newer top-level domains. グーグル has confirmed that it treats the new top-level domains equally. Therefore, using them on your site will not cause SEO issues.