Using ALT Tags in Search Engine Optimization

In the cutthroat world of search engine optimization, site owners, designers, and webmasters are looking for every advantage to improve their search engine rankings. Their efforts have even extended to adding keywords to the lowly ALT tag. Does it work? Yes and no.

The ALT tag is used to provide extra information about images. By putting an ALT attribute in your image tags, you can use text to describe the image. This is helpful in a number of scenarios:

• Users on slow connections will see the ALT text until the image downloads.
• If the image fails to load in the user's browser, the ALT text appears.
• People using text browsers or browsers with images turned off will see ALT text instead.
• Vision-impaired people using audio browsers will hear your description of the image.

But search engines also read ALT information. Because search engine "robots" -- the applications that crawl the Web and compile information about its contents -- can't "see" the images, they depend on the ALT tag for information. The search engines compile ALT tag information with all the other elements of the page, including meta tags, keywords, file names, and myriad other factors, to determine the content of every page of the Web.

This has led some site owners to "spam" their ALT tags, or load them with keywords. While this practice may have worked to briefly improve the search engine ranking of the site in question, search engine technologists quickly caught on. They lowered the weight of ALT tags in their ranking schemes and developed ways to discern between "good" ALT information and spammed ALT tags. The moral of this story? The techs are never more than a step behind the people who seek to exploit the shortcomings of search engine technology.

So what should you do with your ALT tags?

Do: use ALT attributes to accurately describe your images, for all the reason listed above. They may even help your search engine rankings, and they certainly can't hurt it.

Do not: spam your ALT tags. Search engines are way too sophisticated to fall for that -- and abusing the ALT attribute may even get you labeled a spammer and lower your search engine ranking.

As with any aspect of Web design, the goal should always be to make your site easy for users to navigate. This will help ensure that users find what they're looking for and complete whatever transaction you want them to, be it to register, purchase, or just return to your site later. Judicious and proper use of ALT tags can contribute to a good overall site experience, which will help keep your users happy.