So here's the "million dollar question": Which is better, Yahoo Publisher Network or Google AdSense?
Let me make this short and sweet .. YPN is better for well-established websites with US-based visitors, and AdSense is better for un-established - or under-established - websites with a majority of visitors from outside of the US.
Allow me to explain why in more detail.
The number one reason Google's AdSense program has far outweighed Yahoo's Publisher Network is because they've been able to spread out as far and wide as possible in as little time as possible. Some may argue that this has caused Google to stretch their selves far too thin and possibly cause instability in the contextual advertising industry, but that remains to be seen. At this point it is only speculation whether or not either program has become ineffective or unprofitable to advertisers or publishers respectively.
Google has been able to cater to a diverse audience of independent or direct marketers with its AdWords program over the years and they have managed to more than quadruple their shares doing so. This brings us to Yahoo, which has still proven itself in the market second to Google, in contextual advertising, but remains advantageous in respects to displayed and branded advertising from larger firms.
In regards to payout YPN retains generally higher CPC (Cost Per Click) than Google and thus appears more profitable to publishers. YPN also sets a minimum monthly budget for its advertises in order to create advertiser integrity and increase revenues, whereas Google has no minimum spending budget and imposes less stringent screening of their ads.
The only real noticeable difference is that AdSense seems to make a lot more sense. What I mean is AdSense will display far more relevant ads in regard to the content of its pages than YPN. For a website publisher this means that the chances of a visitor clicking on an ad - and thus generating commission for the publisher - are a lot higher with AdSense.
This is what we refer to as a conversion rate; the number of ad impressions made versus the number of times ads have been clicked on. The higher the conversion rate the more money you make as a publisher. So in a sense Google AdSense can more than make up for what it lacks in CPC with what it generates in higher conversion.Both YPN and AdSense are free to join and extremely easy to implement on any website with even the most basic HTML and web-design knowledge. However, YPN requires a little more maintenance than AdSense for one very daunting reason. YPN does NOT allow publishers to display their ads to NON-US visitors, and in fact will boot you from their program for doing so, if even inadvertently. With YPN a publisher would be required to resolve to their own geo-targeting solution in order to prevent ads from being displayed to visitors from outside of the US.
While AdSense, on the other hand, implements geo-targeting directly and serves the ads up on your website with the visitors location already in mind. You can not be penalized by AdSense for which visitors view what ads, simply because they take care of all this for you in-house. This makes AdSense worry-free, requiring virtually no tech-savvy skills, for those website publishers who aren't too familiar with coding.
Another underlying, and sometimes oblique, constraint between the two programs is that you technically cannot use both on the same website. Some publishers will hard-code their websites to display only YPN ads to US visitors and AdSense ads to non-US visitors so that both do not appear on the same web page at the same time.
For YPN this does not seem to cause a problem, seeing as to how their Terms of Service explicitly state that using similar or other third-party advertising is not prohibited given that YPN ads are not displayed on the same web page as ads of a competing contextual advertising program (i.e. AdSense). However, some publishers have reportedly been banned from the AdSense program for using YPN even on the same website. While this is unlikely accurate (since Google will never tell you exactly why it is you have been banned from AdSense) it may be possible, because carefully having reviewed the Terms of Service there are restrictions that seem all too vague, but considerably risky to leave unascertained. But then again Google seems to be changing their Terms of Service for AdSense publishers constantly.
Overall, AdSense seems to be a much faster and effective method of website monetization for the average publisher as opposed to the laggy slower YPN. AdSesne will likely review your website and either approve or deny your application for a publisher account within 2 to 3 business days. YPN may take up to two full weeks. Let's not also forget that YPN has been in beta for several years now.
If you're just starting out as a website publisher and need a fast and easy way to monetize your pages in a hurry, stick with AdSense. However, if you're an experienced website publisher with a large well-established US-based visitor count, you may be able to use YPN to a greater advantage.
