Like it or hate it advertising is one of cornerstones of the web today. Advertising is paying for a lot of the time and money that goes into creating and publishing content that you see online. Without it, a lot of the "free" web sites that make up so much of the web would eventually disappear. This same pattern looks set to continue on the mobile web — mobile-specific ads running on mobile sites will eventually become mainstream as the mobile web becomes more popular. Mobile advertising is a very hot area right now and there are many companies promoting services, some of which are ready, but many of which are not. This article will survey some of these service and determine which ones are most useful to mobile site developers today.

There are two primary ways that internet advertising can help with a mobile web site:

1. Driving traffic to your site with paid-for ads or keywords on other sites and search engines
2. Embedding ads on your own site in order to monetize traffic from your own users

This article will focus on case 2 above — web developers wishing to monetize a mobile site using advertising rather than those wishing to advertise elsewhere to drive traffic to their sites. This article will concentrate mostly on "self serve" advertising, where site owners set up ads to embed in their own sites via a web-based process. Why focus on this use case? Well, it was really self-serve ad services like Google AdSense that really made advertising accessible to the masses. Being able to do this over the web without having to sign agreements and negotiate contracts in person has made the whole process transparent, open and efficient.

Embedded web advertising takes two forms: banners (images) and text links. In the early days of internet advertising ad banners were by far the most predominant form of advertising, and usually took the form of GIF or JPEG images in a set of standard sizes (now defined by the Interactive Advertising Bureau) e.g. 468 x 60 and 234 x 60. Clearly these large images won't work well on mobile devices so self-service mobile advertising is currently mostly implemented using simple textual links embedded in other content. This is the method used by many of the companies looked at in this article including AdMob, DeckTrade and Medio. Small banner ads are also served up sometimes, depending on the capabilities of the phone. The following ad comes from DeckTrade:

Flash ads are becoming more popular on desktop-oriented web sites but it will be a while before this becomes popular in mobile.

Google

Google is the clear leader in advertising on the desktop-web with their AdSense and Adwords services. But what about the mobile web? Is Google's enthusiasm for mobile reflected in their advertising offerings? There are two sides to Googles advertising services, AdSense and AdWords.

AdSense

AdSense is the name given to the small contextual advertising panels you see embedded in sites all around the web. At the time of writing (May 2007) Google does not yet have an equivalent to AdSense that works on mobile web sites, though this seems very likely to change in the near future. Google's knowledge of what a page is about will be a powerful tool to help ensure that their ads are meaningful and appropriate.

AdWords

AdWords are the paid-for links that you see when you search the web using the Google search engine. Google also offers a mobile version of this service. Mobile ads are shorter text-based AdWords ads that appear when users search Google from a mobile device. When users clicks on your mobile ad, you can send them to your mobile web page or offer them the option to connect to your business phone. Mobile AdWords can easily be enabled within you existing AdWords settings. You can find instructions for doing this on the Google site: http://adwords.google.com/support/bin/answer.py?answer=29488

Since this article is concerned about monetizing a mobile site rather than advertising your site in seach listings, mobile AdWords will not be covered in any further detail here. The table of contents for Google's ad services for mobile can be found here: https://adwords.google.com/support/bin/topic.py?topic=8500

Yahoo

Yahoo appears to be planning to offer a self-serve advertising service for website owners and there was a lot of coverage in the press around the time of 3GSM 2007. From their website:

"The Yahoo! Mobile Ad Network gives you tools that make it simple to serve this syndicated advertising on your site – you choose from display ads, sponsored links, video spots, in–game or in–application placements, etc – depending on what is most relevant for your business. When the ads are served (or clicked on), you make money."

but when I tried to sign up for this service it seems like it is still in trials:

"Thank you for your interest in becoming a member of Yahoo!'s Mobile Publisher Network. We have received your submitted sign up form. We are selling and soon serving mobile advertisements for a select number of publishers, and we are currently considering new publishers as we expand the program."

So, no luck yet but we'll keep an eye on this and update this article if we get a chance to actually test this.

Nokia

In March 2007 Nokia announced a suite of new ad services for mobile based around the nokia.mobi portal. Nokia’s ad server takes the standard approach of providing publishers with a set of links for embedding into their site. The Nokia ad server will make the selection of the most appropriate ads based on various criteria. These are enhanced if the user has the Ad Connector client installed (S60 devices only at the moment) which will then provide context by logging the sites you visit, and what types of content you surf.

The publisher can sign up in a simple way using the self service web pages, which ironically still require you to phone up first, to set-up the relationship and contract. Nokia are talking of “PCM” around US $40 and are basing this number on the following:

• that mobile advertising has click through rates of about 10X the web, hence 10x
• that they need to pay a premium to start building market share, because they cannot rely on their brand alone (especially in America where their brand is less strong)

Thanks to Steve Devo of dot-m consulting for this information.

AdMob

AdMob appears to be the leader in self-serve mobile advertising right now. AdMob offer two main advertising services:

• create ad campaigns for placement in the AdMob network of sites
• run ads from the AdMob network on your own site

Of these two services, the latter is of more interest to people trying to monetize a mobile site.

Signup is easy. AdMob require only an email address and a password. Payment for ads that you serve on your site can be by Paypal or cheque. You can optionally enter a Federal Tax ID or Euro VAT number if you have one. The ad serving set up is fairly easy: AdMob allows you to set up a number of sites with different advertising settings. For each site that you set up, you are invited to enter a description of the site to help AdMob advertisers choose whether or not they want to pay for ads to show up on your site. Site owners are allowed to choose whether or not they want adult ads to show up. AdMob also lets you approve/disapprove specific advertisers on a case by case basis. This seems like a good idea because you may know that your users are unlikely to click on certain non-relevent ads — targetting the ads to your audience is good for you (your bank account) and your users (more relevent ads).

Embedding the Code

Once you have set up your site within your AdMob account, they make available a set of code templates to enable you to easily add the ad links to your site. Unlike the desktop web, mobile ad providers can't rely on Javascript code in running in the browser to fetch the most relevant ad — the ad links need to be in the page before the phone receives it. AdMob makes available code snippets for PHP, JSP, ASP, Perl, VB.NET, C# and Ruby on Rails. The code is very straightforward and easily adapted to work on other languages (it took me just a few minutes to make a Python version). Here's the PHP version:

For those who don't have the ability to dynamically generate these links on their websites, you can embed a static link in the following form:

Great Mobile Sites

though clearly ads served in this manner will not be as effective as the dynamic versions, since the label of the ad never changes, though the target can.

Once the code is in place in your site, viewing the page will result in something like this (http://cremin.mobi/):

Clicking on the link that was now embedded in this page resulted brought me to the following page:

In theory, every time the page containing the ad is reloaded, the link text and target of the ad can change. You can see from the code above that AdMob are using both the User Agent and phone IP address (or the WAP gateway IP address to be precise) to help target the ads. This isn't always successful: less common user agents sometimes cause this algorithm to fail e.g. when I tried the site above on an N800, the ad text was something like "Get ringtones for your 1". The IP address logic seems somewhat problematic: I regularly see ads in Spanish, which doesn't seem that targetted given that my WAP gateway IP address is in Ireland. That said, since AdMob allow you to tailor the ads that show up on your site, this can be remedied fairly easily, by hand.

One potential issue with the way that this system works (and the same for Deck Trade) is that every page view results in a call to the ad servers to get the text and link of a new ad. While this should normally happen very quickly, it is possible that delays in getting this URL could slow down the page rendering on your site.

Revenue Model

AdMob's revenue model is based on cost per click (CPC) model and they share revenue 60/40 in favor of publishers for CPC ads and a 50/50 split for CPM Graphical Banner ads. Admob issue checks the first Monday of every month and pay 30 days net (eg. all earnings in March will be paid the first Monday of May), but you must have at least a $20 balance in your account for this to happen.

Advertising Services List

* Portion of revenue that goes to site owner

An Experiment

Rather than reporting on these services in a purely abstract way, we're going to try an experiment: we are going to run a series of ads from some of the advertising companies above on the mobile version of mobiForge, and let you know how it goes in a few weeks time. We'll be careful to rotate the ads randomly to ensure that the results are as fair as possible. By then it should be clear which advertiser is generating the most revenue and whose ads are most relevant. Most of the advertising service have categories for ads that include ringtones, TV & Movie, Personals etc. For all of the ad services we are trying, I've signed up to all channels to make things as fair as possible, so you are going to see some pretty untargetted ads on mobiForge for a while. All in the name of experimentation..