Links are a way to “vote” for another web site and therefore increasing that web site’s popularity, often referred to as link popularity. Link popularity is a measure of the quality of a web site.

Links from other web sites to your web site will increase your link popularity. The more links to your web site, the better your link popularity and consequently search engine rankings.

Put simply, the more links to your web site => the more “votes” your web sites has => the more popular your web site => the higher your search engine rankings.

Link popularity is the basis of many search engine algorithms. The search engine Google was the first to use link popularity as a major factor to judge a web site’s quality and worth. It is now used by other major search engines such as Yahoo! and MSN.

What are links?

The term links stemmed from the word, hyperlink. Links are references to other documents or resources in a hypertext document.

There are two ends of a link, the source and the target.

The most common type of targets are URLs. These URLs are most often web pages, either on the same site, or on a different site. Other targets can include other resources such as a file, an image or a position on a web page.

How is a link created?

To create a link on a web page, we use HTML code that contains some or all of the following five main characteristics:

• a link destination (”href” pointing to a URL)
• a link label (the anchor text)
• a link title (the title of a link to specify more information about the link)
• a link target (where the link will open)
• a link class or link id (for CSS styles)

The link destination of a link is most often another web page, either on the same site or on a different site.

The link label, also known as the anchor text, is the visible part of a link on a web page. The link label can be a string of text or even an image.

The link title is an attribute of a link. It is a string of text that describes the link or more accurately, the link destination, in more detail.

The link target specifies which browser window the link will open in. Typical link targets are:

• target="_blank" to open a link in a new, blank window.
• target="_top" to open a link in the full body of a window. Most often used to break out of a deep frame nesting.
• target="_self" to open a link in the same window the link was in. Most often used to override a globally assigned base target.
• target="_parent" to open a link in the immediate frameset parent of a document.

The link class or id is used to identify the link. By specifying a link class or id, the style or look of a link can be altered using Cascading StyleSheets.

Links are created using the HTML anchor tag (<a>) with all or some of the above link characteristics.

Examples of links

An example of a generic link.

An example of a link to Link Tutorial’s homepage.

Which results in:

When you mouseover the the link label above, “Link Tutorial”, you will notice your browser’s status bar will display the link destination, “http://www.linktutorial.com”. Additionally, when the you hover the mouse cursor over the link labe, you will notice the link title pop up. In this case, the link title is “Link Tutorial homepage”. With a target of “_blank”, the above link will open and load the link destination a new browser window when clicked. The class and id of the link can be used to define the style or look of the link using Cascading StyleSheets

Why are links important?

Put simply: Links are the internet’s currency.

It started when Larry Page and Sergey Brin developed a system of ranking web pages based on the number of incoming links and outgoing links on a web page. This system of ranking web pages was the basis of the Google search engine. The system proved to return search results that were far more useful and relevant to users. This basic system of ranking web pages was so successful that it’s now employed, in some way or another, in the other major search engines such as MSN and Yahoo! Search.

When “black-hat” search engine optimizers discovered that having more links to your web page increases the rankings in Google’s search results, they started to use spammy link techniques. Due to the large amount of spammy, artificially created links, the system has now developed into a far more complex system.

Further reading

For more detailed information about links and their history, see Wikipedia’s definition of a hyperlink.