HTML and CSS Reference
The <aside> tag, which represents a section of a page content loosely connected to the content around the
<aside> element, means that if the ad server contextually served the advertising message, the <aside> tag would be
an accurate container for the ad to live inside of. This would most likely only work if the publisher had specific ad
inventory slotted out for contextual experiences. Take a look at the example in Figure 3-2 on a sample HTML5 page 3.
Figure 3-2. Markup of section and aside elements in the browser
Another interesting feature in HTML5 is the new data attribute. This attribute addition may seem a bit crazy at first,
but it offers some really good use cases, especially in the advertising space. Using the data attribute in your ad's
markup, you can customize specific values on a certain element. For example, in ad serving, what is called a macro
is often used to replace a variable with other values at ad serve time; how it is used depends on the publisher the
ad is being served toward and on other information we can learn before rendering the ad to the page. This macro
value, which is very similar to a variable in traditional coding languages, will typically look like $MACRO$ , ??MACRO?? ,
or something pretty similar depending on the ad-serving company and its ability to parse on a specific character in
order to insert a value. The macro value can be added to the ad's markup via the data attribute; when the ad is
served, that attribute will get replaced by the value that should be there, per the information the ad server gathers.
Listing 3-1 showcases how this would work by replacing a click URL for an ad to enable the same ad creative to serve
many publishers. The fact that the click URL can dynamically change based on the ad servers helps if you want to
traffic the same creative across multiple publishers but still want to have unique click URLs.