Banner Advertising and Accessibility

Thursday, 6th May 2004

Author: Roberto Scano

Definition of a Banner

Source: (Webopedia).

Also referred to as a banner ad, a banner is typically a rectangular advertisement placed on a Web site either above, below or on the sides of the Web site's main content and is linked to the advertiser's own Web site. In the early days of the Internet, banners were ads with text and graphic images. Today, with technologies such as Flash, banners have gotten much more complex and can be ads with text, animated graphics and sound. Most commerce-related Web sites use banner ads.

Standards for Banner Advertising

Starting in August 2002, the Ad Sizes Task Force began a process to reduce the number of ad sizes for the purposes of reducing the costs and inefficiencies associated with the planning, buying and creating online media. The result was the Universal Ad Package, a set of four ad sizes that all compliant member publishers have agreed to support:

728 x 90

• gif/jpg weight limit: 20Kb
• flash weight limit: 30 Kb
• max animation length: 15 seconds
• no border

300 x 250

• gif/jpg weight limit: 20Kb
• flash weight limit: 30 Kb
• max animation length: 15 seconds
• no border

160 x 600

• gif/jpg weight limit: 20Kb
• flash weight limit: 30 Kb
• max animation length: 15 seconds
• no border

180 x 150

• gif/jpg weight limit: 15Kb
• flash weight limit: 20 Kb
• max animation length: 15 seconds
• no border

The Interactive Advertising Bureau's (IAB) new wave of voluntary guidelines includes seven new Interactive Marketing Unit (IMU) ad formats; two vertical units and five large rectangular units. The new voluntary guidelines join the roster of recommended guidelines that the IAB already has in place. These units are currently being introduced by Web publishers and are designed to enable marketers to utilize greater interactivity as well as expand the creativity in their online messaging. The IAB's Ad Unit Task Force will meet on a bi-annual basis to examine the effectiveness of existing ad units; review proposed new ad units; and issue updated voluntary guidelines as appropriate. A full definition set for all these banners is available from the IAB website.

The sizes are a 120 x 600 "skyscraper," a 160 x 600 "wide skyscraper," a 180 x 150 "rectangle", a 300 x 250 "medium rectangle", a 336 x 280 "large rectangle", a 240 x 400 "vertical rectangle" and a 250 x 250 "square pop-up" ad. The IAB also said it would no longer include the 392 x 72 pixel banner from its recommended sizes, since that size is rarely used.

Accessibility for Banner ad

What is the main problem for the banner ads? A lot of banner ads are simply images (jpg and gif) and must respect the guidelines for Core 1.1. We can divide the banner ads in six big groups:

• text ads
• image ads
• flash ads
• javascript/pop-up ads
• skyscraper ads
• Webmercial ads

Text ads

Text ads are the "simply ones" that are available. For accessibility for people with low vision, the text must be expressed in % or .em for the user to resize it. Text ads must advise the user that the link is an advertising link so the suggestion for the code is:

<a href="http://www.banneradserver.ext?id=xxxx" 
  title="(banner)">
 Product name or Promotional message</a>

Image ads

The user must have the possibility to know that the image is a banner ads so the combination of "title" and "alt" attributes can help during the navigation (with eventually a "longdesc" if there is the necessity to describe the banner AD images and/or animation). Here is an example:

<a href="http://www.banneradserver.ext?id=xxxx">
    <img src="banner.gif" width="120" height="60" 
    alt="(banner)"
    title="Product name - promotional message in plain text" />
</a>

If the banner contains an animated gif, this can also cause reading problems to users with cognitive disability or for low vision people and if there is screen flicker - Core 2.3.

Flash ads

What about Macromedia Flash animated banners? Following the guidelines, the object tag must also respect the guidelines for Core 1.1.

<object type="application/x-shockwave-flash" data="movie.swf"
        width="250" height="250" 
        title="(banner) Product name - promotional message">
    <param name="movie" value="movie.swf" />
    <a href="http://www.banneradserver.ext?id=xxxx">
    <img src="noflashbanner.gif" width="250" height="250"
    alt="(banner)"
    title="Product name - promotional message in plain text" />
    </a>
</object>

In the example, if the user does not have support for Flash, there is the image as an alternative with the possibility to follow the link if the image is not available.

javascript/pop-up ads

Sometimes, there are banner ads that are generated by JavaScript code. This means that the user must have the script engine activated. The banner is requested to conform to Core 2.1. JavaScript is also used for pop-up the banners. Pop-up windows are ads launched into a new, smaller browser window when a page is loading. Pop-up windows can easily be targeted to launch over a specific page, a feature that not all interstitial technologies provide. Pop-up windows are most commonly run by attaching JavaScript launch code to a banner ad. This allows the pop-ups to be frequency-capped or targeted using any ad management system's targeting capability. Because pop-up windows are simply smaller browser windows, they can contain any standard Web display format, including HTML, GIF, JPG, and Macromedia Flash.

Skyscreaper ads

Also called Redwoods or Towers, these ads are usually found off to the sides of web pages. They provide a large advertising space while utilizing normally unused web space. This kind of banner can only be activated by the onmouseover on onclick events so these are not accessible and not conform to Core 2.1. These banners must be offered an alternative version, similar to the Macromedia Flash example.

Webmercial ads

Unlike banners, webmercials feature full-screen animation accompanied by professional voice-over and sound effects. They appear in the primary browser window between Web pages for 5-30 seconds. Webmercials can also be shown while viewers are waiting for a file to download or a search to be completed. Because of this unique delivery, webmercials are much more effective than TV commercials-even for branding purposes. These ads, due to the multimedia equivalents requirement, must conform to Core 1.2.

Category: Accessibility.