If you've recently been given the boot by Google Adsense or are simply curious about how well the alternative PPC engines perform, have I got some jewels for you.

I've recorded the average earnings, pluses, and minuses in a trial of several of the most popular PPC web master programs on a high traffic site (not this one =)). Each trial ran for about 1 week.

My reviews listed below are graded on a scale from A to F. I included testing of pay-per-click and pay-per-sale (affiliate) programs. All programs were tested on a contextual-advertising basis. That is, I was only concerned with showing ads which matched the content of pages. I was not interested in graphic banner ads or popups.

So, for those of you wondering how the rest of the PPC world is doing, here it is:


Yahoo YPN

I have heard earnings in YPN can rival Google Adsense. The program is still in beta which may be the reason they are choosy about who to accept. After submitting the application for a heavy traffic site, I received an acceptance reply after 1.5 weeks. Their system operates very similar to Google, but with one major difference - their Terms of Service. While Google barely lets you change text on your site, Yahoo's agreement is much more relaxed. After the first day, earnings were comparable with Google, if not higher. Their system seems to lag behind in statistics, but it may just be updated daily. Yahoo may be a serious contender for Adsense.
Average earnings per click: $0.50 - $1.00
Click Frequency: Good
Grade: A


TargetPoint

The ads are quite relevant and receive a good click-through rate due to color and look. However, their pay-rates are incredibly off. I saw statistics of 70 clicks or more earning a total of only $0.25. I'm not sure if they are inserting free ads along with paid ones or if their payout really is a fraction of a penny per click. I emailed support to explain this and they responded by mentioning they offer a higher-tiered program for heavier traffic sites. They provided additional code for the higher tier. The PPC rate appeared to increase to about .10 per click, but the ads were not relevant to the content like their standard ads are.
Average earnings per click: $0.005
Click Frequency: Good
Grade: B


Clicksor

Ads open in a popup window, which is not the greatest idea since many users are blocking popups these days. It also takes several days before the ads become relevant to your content. Even then, the relevancy is not that great, which can result in poor click-through ratios. One good point is that Clicksor offers in-text links, where a keyword becomes a hyperlink to an ad within your content. This is in addition to banner ads. However, because Clicksor's relevancy is so poor, you will be unlikely to get many clicks, which puts its earning potential closer to TargetPoint. I tried emailing support to ask about the relevancy issue, but have received no reply. Their ad creation system also has problems. Upon setting the account up to only show in-text ads and not banner ads, their system continued to request banner ad data.
Average earnings per click: $0.07
Click Frequency: Poor
Grade: C


Kanoodle BrightAds

One of the 2nd-tier search engines, Kanoodle's PPC program offers contextual ads, popups, pay per cookie, and a few more. As of this time, I have yet to hear back on my application.
Average earnings per click: $-.--
Click Frequency: -
Grade: -


Quigo Adsonar

Adsonar is still somewhat in beta and, as such, is only accepting a very limited number of web sites to join up. I went and applied. About 1.5 weeks later I received a rejection email. Thus, I can not review how good they were. Hopefully when they add more categories they will accept a broader range of sites.
Average earnings per click: $-.--
Click Frequency: -
Grade: -


Clickbank

As the first test in contextual-based affiliate ads, Clickbank has the easiest affiliate system to get up and running. After downloading their .xml feed product list, I could query it locally to find matching ads. There is no need to join any specific programs. You simply tag on your ID to the URL for a product to begin advertising it. I can safely say they do pay and send out checks monthly. However, many of their products are MLM or make-money-fast, and give a "dirty" feel towards advertising them. Even with contextual ads combined with their product database, it was difficult to get a broad enough spectrum, and even more difficult to get a sale. On the bright side, just 1 sale was enough to top any of the pay-per-click advertisers, although getting that 1 sale can be difficult with Clickbank's army of products.
Average earnings per sale: $12.00 - $50.00
Click Frequency: Average
Grade: C+


Amazon Associates

Similar to implementing Clickbank and contextual matching, I put Amazon's affiliate program to the test. This one is tricky. They offer a really great API, called Amazon ECS, which lets you write code to query their database and find products, as opposed to Clickbank's .xml file. Well, if Amazon had an xml file, it would be several gigs in size. I used the AmazonECS.NET API to talk to their database. The biggest problem is the poor quality matching on Amazon ECS. You pass them keywords and they return a list of matching Amazon products. However, their relevancy rate hovered around 30%. Of course, this resulted in low clicks. Another problem, the amount earned per sale is a pitiful 4% - 6%, compared with Clickbank's 25% - 75%. While Amazon does have a much larger database, their search function did not work well enough to judge results.
Average earnings per sale: $2.00 - $10.00
Click Frequency: Average
Grade: B-


AffiliateSensor

They claim to have contextual relevant ads, but they are only relevant if you specify an H1 tag. Upon inserting their code, there were javascript errors. Their ads also do not appear to match relevancy for the page content. They insert their own affiliate id for 5% of the displayed ads and the id of the person who refered you for another 5% of displayed ads. I believe their system could use some work.
Average earnings per sale: $10+
Click Frequency: Poor
Grade: C


Want more? Let me know the program names you want to see and I'll consider giving them a trial run and post the results here.