AdSense Highlights

Stef was impressed by what she heard. "My friend John, the guy who set up my blog for me, is always raving about Google and the cool things they do. I guess this is one of them!"

"They've definitely created a cool system," I agreed. "What's really interesting about AdSense, though, is how quickly it's evolved. The AdSense program was actually fairly limited when it was introduced in 2003: There were only four ad sizes to choose from, image ads were not supported, and there was no detailed tracking of visitor clicks. Publishers asked for more features, however, and soon these limitations were removed." I then summarized the important features.

Different Ad Types

AdSense offers two types of ads: conventional text and image ads, which jump directly to an advertiser when clicked, and ad links, which open a page of ads when clicked. Ad links list topics, not individual advertisements. Ad links are more compact than the traditional type of advertisement, but when they are clicked they display more ads than you'd see normally.

Multiple Ad Formats and Sizes

AdSense supports three regular ad formats, with several ad sizes in each format. A particular combination of an ad format and an ad size is referred to as an ad unit. Each ad unit displays a set of text ads or a single image ad. (Ad links all follow the same general format, though their size and the number of links varies. The units are referred to as ad links units.)

The first format is the banner format, the classic rectangular advertisement format where the width is substantially larger than the height. Each text ad in a banner is the same height as the banner itself (Figure 2.4). A wide banner is sometimes called a leaderboard.

Figure 2.4. sample AdSense banner ad.

The second format is a tower (Figure 2.5). A tower is basically the opposite of a banner, its height substantially larger than its width. Text ads are as wide as the banner and are stacked on top of each other. A tower is also called a skyscraper.

Figure 2.5. A sample tower ad.

The final format is the inline rectangle, a rectangle whose dimensions are roughly (or even exactly) equal. Unlike banners and towers, which are normally placed on the edges of a Web page, inline rectangles are often inserted directly in the middle of a Web page (Figure 2.6). Text ads shown with the inline rectangle format are stacked on top of each other just as they are in the tower format.

Figure 2.6. sample inline rectangle ad.

A good selection of sizes is available within each format. The smallest sizes display one or two text ads, while the largest display four or five. Note that image ads are supported by only a few of the sizes, so your choices are more limited if you want to display image ads within an ad unit.

Flexible Ad Unit Placement

You can place AdSense ads anywhere on a page as long as visitors don't confuse them with the actual content of the page. Google helps avoid any confusion by drawing a border around the ad unit and by labeling the ad unit with "Ads by Google" or words to that effect, though you can remove the border by changing its color.

Up to three ad units can be placed on a single page. Many sites display just one ad unit per pageyou don't want to overwhelm visitors with advertisements. Each ad unit can be a different size and format, though, so it's not uncommon to see pages with a tower on the side and an inline rectangle right in the middle of the page text.

Add Ad Units

Start with just one ad unit and see if that fills up. If it does, then add more units.

A downside to using multiple ad units on a page is that there may not be enough ads available to fill them all and you may end up with wasted space on the page.

Customizable Color Palettes

The default AdSense color scheme is the same scheme used for sponsored links on Google's own search pages: blue title, black text, green URL, white background. Not every site looks like Google's site, though, so AdSense lets you change the colors to suit your own site's color scheme. Even different ad units on the same page can have different color schemes.

An individual color scheme is referred to as a color palette. AdSense includes a number of predefined palettes that can be used by many sites. These palettes have colorful names like "Mother Earth" and "Peach Melba." If none of the built-in palettes suits your needs, though, you can create your own custom palettes.

For variety, each ad unit can rotate through as many as four different color palettes, though a single palette per unit is the norm.

Alternative Advertisements

Despite its best efforts, AdSense can't always fill an ad unit with relevant advertisements. This can occur for a variety of reasons:

• No or few ads match your content.

• The only ads available are ones that you're currently blocking (see the section on ad filtering below).

• There are matching ads, but the advertisers have exceeded their daily budgets.

As long as one or more ads are available, AdSense displays them and fills the rest of the ad unit with the background color. The problem occurs when there are no ads to display. Rather than show an empty box, AdSense displays one or more public-service advertisementsPSAs for shortin the ad unit. PSAs are free advertising that Google offers to charitable and other nonprofit organizations. Visitors can click PSAs in the same way as they click normal ads, but you don't make any money from those clicks. If you want to make money, you want to avoid PSAs.

Black Hole Ads

If you're truly adventurous, you can even make empty ad units collapse to nothingsee www.memwg.com/collapsing-ads for the details.

Instead of displaying PSAs, you can ask Google to display alternative content in the ad space by providing Google with the URL of some other Web content. The URL might point to an image you've placed elsewhere on your site, to a page fragment you've created, or even to a different advertising service. It doesn't matter what it is, as long as it fills the space allocated for the ad unit. (The space will not be boxed or labeled by Google, of course.)

If you don't have any alternative content to display, you can simply display a colored box that matches the color of the surrounding page area, effectively erasing the ad unit from the page.

Channel Tracking

When AdSense was first introduced, there was no way to track which pages on a Web site were generating the most revenue. After receiving many complaints about this, Google allowed publishers to group pages into channels and track revenue on a per-channel basis. Publishers could create up to 50 (the limit's since been increasesee Chapter 7) custom channels to spread however they wanted across their sites.

One problem with custom channels is that they require modification of the AdSense JavaScript code that gets pasted into each Web page. AdSense will generate the modified code for you, but you have to generate the code for each channel and paste it into the appropriate pages. For a large site, this becomes a bit of a maintenance headache, especially if the AdSense code is otherwise identical across all pages. AdSense now lets you create URL channels, channels that track revenue based solely on Web addresses. You can create channels for each page, for groups of pages, or for entire Web sites, all using the exact same AdSense code.

URL-Based Ad Filtering

Sometimes you don't want to see certain ads appearing on your site, especially if those ads are promoting products or services that directly compete with the ones that your site is promoting. AdSense lets you indirectly block these ads using a facility called URL filtering.

URL filtering blocks ads based on the Web addresses they link to. You provide AdSense with a list of Web addressesup to 200 of themand AdSense ensures that no ads that link to those addresses appear on your pages. It's not a perfect solution by any means, but it works well enough for most sites.

Detailed Reporting

From the publisher's standpoint, one of the great features of AdSense is the detailed reporting available through the AdSense management console. You can track revenue by date and channel and even know when Google has mailed you a payment check. And the great thing is that the really important informationhow much money have I made today?is updated continually throughout the day as visitors click the ads on your site.

Monthly Payment

Another great thing about AdSense is that Google pays publishers on a monthly basis. About 20 to 30 days after the end of a month, Google mails each publisher a check for the prior month's earnings. Note that you'll only receive a check if you've earned at least $100; otherwise, your earnings will be rolled over into the next month.

AdSense for Content

The introductory AdSense for Content page is at www.google.com/adsense/afc-online-overview.