Content Copyright © 2006 Bloor. All Rights Reserved.
Adverts are an essential part of the web; the revenue from web advertising is now comparable to print advertising. The revenue contributes to the running costs of the website; without this revenue many websites would not be viable and the information supplied by them would not be available to the punters.
The content and format of the adverts is produced by the advertiser and may not adhere to the usability and accessibility requirements of the site.
Before I describe the issue in any more detail, and before anyone suggests to me that people in glasshouses should not throw rocks (as one of my readers did recently), I need to point out that my articles are published and syndicated on several sites. If you are reading this on a site that does not meet my exacting standards, I am sorry, but please complain to the site owners and not to me.
Adverts to be worth the cost have to attract the reader. The problem is that many techniques used to make the adverts stand out, and attract the reader, can have a negative impact on the usability and accessibility of the site. These include:
- Pop up windows
- Flashing images
- Imbedded links
Any advert on a website should abide by the W3C WAI guidelines.
Here is an initial suggestion for a set of rules for the host website to apply to adverts that will go on the site:
- Provide a text equivalent for every non-text element (e.g., via “alt”, “longdesc”, or in element content) in an advert. An advert is very likely to be an image; the advertiser must supply text that the host site can use in the alt tag. Defaults are no good, I have seen sites where the alt tag for an image for an advert says ‘Here is where the alt information should go’!.
- If clicking on an advert will open another window, which seems a reasonable option, then the host site must tell the user that this is going to happen. The user should also be told where they are going.
- Many adverts having moving parts to them then ideally they should stop after a short time. One run through of the video or possibly two if it is short. People with dyslexia and people with some visual impairment find movement at the least a distraction and at the worst aggravates the condition (in fact I find it very difficult to concentrate on text if there is movement on the edge of my line of vision).
- Flashing on a screen can set off an epileptic fit so adverts should not flash or change very quickly. I have seen adverts that have some sort of countdown 10,9,8… in very quick succession and that could be sufficient.
- Adverts that are simple HTML should abide by all the rules of WAI and in particular should allow text to be sized.
Host sites should not accept adverts if they do not abide by these requirements. This may sound like bad business practice but I believe that after a short time the advertisers sill recognise the benefit of being on an accessible host site and the benefit of the adverts being accessible.