Such pages sought to look the same in all browsers of a certain age (such as Microsoft Internet Explorer 4 and Netscape Navigator 4), but were often inaccessible to people with disabilities.
Tag soup pages also displayed or operated incorrectly in older browsers, and required code forks such as JavaScript for Netscape Navigator and JScript for Internet Explorer that added to the cost and complexity of development.
The extra code required, and the lack of a caching page layout language, made web sites "heavy" in terms of bandwidth, as did the frequent use of images as text.
These bandwidth requirements were burdensome to users in developing countries, rural areas, and wherever fast Internet connections were unavailable.
"They are a way of creating Web pages that will facilitate the twin goals of sophisticated and appropriate presentation and widespread accessibility.
It then set about promoting these standards to designers, who were still using tag soup, Adobe Flash, and other proprietary technologies to create web pages.