ALT text, or alternative text, is embedded content that is meant to describe an image that appears on a webpage. It is HTML code and not normally visible to webpage viewers. Its purpose is to convey the meaning of images to viewers who, for a variety of reasons, cannot or do not view webpage images. These persons can include the visually handicapped or those whose browsers do not support images.
ALT text should be nothing more or less than a concise description of the image it is supposed to describe/replace. For example: “The Statue of Liberty viewed at sunrise.” The ALT text should not contain any additional information other than that necessary to convey the same information that the image itself provides; for this reason, many HTML coders simply use the image’s caption as ALT text, though it is easy to think of instances where the caption alone would be insufficient as a description of the image.
The primary user of ALT text is the visually impaired individual who uses a screen reader (software program, not human reader) to read text aloud for him. The “alt” coding alerts the reader that it should not read the sentence literally (i.e., with all the graphics and punctuation characters read aloud) but rather, should only read the actual captioning or description. This has proved to be a valuable aid for these users, particularly when comprehension of the webpage is partially or wholly dependent on the viewing/comprehension of its images.
Other “readers” of ALT text are search engine bots; these programs interpret ALT text as webpage content. Unfortunately, the lack of search engine sophistication led in recent years to the practice of “keyword stuffing,” where webpage authors felt (correctly to some extent, at least at first) that the way to achieve high search engine rankings was to insert keywords everywhere possible on the website. This led to bad grammar and artificial-sounding writing in webpage content, with the inclusion of keywords being all that mattered. Later, search engines became more discriminating and downgraded keyword-stuffed websites, which meant that content writers resorted to a few “tricks” to embed a plethora of keywords, such as making them invisible to the reader, or at least to the search engine’s discriminatory functions: the engines would check for keywords in the usual fashion but would only check visible content for relevance. This resulted in such farces as background wallpaper that repeated a keyword 500+ times (“salami salami salami salami salami salami”) or HTML instructions that were superfluous but contained many mentions of a keyword. The idea was to make the website appear as if it had not been keyword-stuffed.
The effect on ALT text content was dramatic. As “invisible” text, it was an ideal place for webpage developers to embed keywords without having the search engine downgrade the site as a result. However, the effect on impaired-vision readers was drastic: the voice reader would now recite: “The Statue of Liberty at dawn salami salami salami salami salami salami.” This would obviously frustrate the visually-impaired website visitor and damage his viewing experience. This effect is also frowned upon by the Americans with Disabilities Act (ADA), which monitors, among other things, websites for compliance with its guidelines and tenets.
The tactic of concealed key-word stuffing is no longer effective, due to the greatly increased sophistication of search engines. In fact, keyword-stuffed (“concealed” or not) websites are consistently downgraded for that reason alone. Thus, keyword-stuffing in ALT text destroys the website viewing experience for the visually impaired, while not only providing no benefit for SEO but also downgrading a site’s search engine ranking. Yet, a surprising number of website developers still engage in keyword-stuffing, which is almost these days like search engine anti-optimization: it artificially lowers a website’s rankings.
The website developer shouldn’t abandon the use of ALT text, but should continue to use it in the way it was intended: as an alternative to images. There’s nothing wrong with using a keyword in the ALT text if that keyword happens to be part of a proper and concise description of the image. However, you need to be aware that (because of prior abuses, as above) keywords inside ALT text are ignored when SEO rankings are generated.
A good general rule to follow in all aspects of webpage construction is that your content shouldn’t appear artificial or “forced.” After all, the intent of webpage content—its purpose—is to engage and inform human viewers, not search engines. Unfortunately, because of the lack of sophistication in search engine algorithms, for most of the past decade or so, ranking high in brute-force search engine selection was paramount: you had to get visitors to your website, and the only way to do that was to cater to the needs/demands of the search engines, even if those demands amounted to “Give us garbage with lots and lots of keywords.” The search engines have changed; they have grown in sophistication. The very tactics that used to be ideal for SEO have now boomeranged; if you use crude, keyword-stuffed, artificial-sounding content, your website will be downgraded as a result.
Many website developers over the last few years have focused their energies on “fooling the search engines”: tweaking their content so that a website receives a higher ranking than it would “deserve” based on its content’s relevance alone. It’s hard to say whether this was driven by the crudeness of early search engine algorithms or a need to provide the best rankings even by “gray” tactics (those of questionable propriety), but that’s largely irrelevant; there’s now no need to try fool the search engines since they check for good construction of content as well as keyword relevance. There’s also no need to ruin your ALT text with keyword-stuffing, or for that matter, to garbage up your HTML in order to make it appear more enticing to the bots. We’re past all that now, and the effect can only
be to make website content better written, cleaner, and more engaging to us humans—the
ones for whom webpages are supposed to be designed.