To be able to compete with Google Adsense, however, YPN is still long way to go. Or, in other words, it does not want to compete with Adsense for this time around.

Look for example at its beta version now. YPN just want American publishers, not others. Not you, non-US residents. Here what YPN requirements in the sign-up form:

To be considered for the Yahoo! Publisher Network beta program, please enter your information below. Participants of the program must have a valid U.S. Social Security or Tax ID number, and web site content that is predominantly in English and targeted at a U.S. user base. Yahoo! will contact you about your eligibility to participate and about availability of the program.

Yahoo! Publisher Network does not wish to be associated with certain types of content, behavior and/or products. Please refer to our Content Guidelines for a list of content types that we will not serve ads to.

Apart from that, YPN seems to have similarity in terms of quality content a publisher should and should not have to be eligible as Yahoo Ads publishers:

Yahoo! Publisher Network Content GuidelinesYahoo! Publisher Network does not wish to be associated with certain types of content, behavior and/or products, and will not accept sites that contain this type of content. This includes, but is not limited to:Adult-oriented content
Violence, excessive use of vulgar or obscene language
Excessive, duplicate or competing advertisements
Content related to human suffering or death
Copyright or trademark-sensitive products such as MP3 downloads, DVD backups or bootleg items
Weaponry, ammunition, fireworks or explosives
Gambling
Illegal drugs and drug paraphernalia
Propaganda, potentially offensive or controversial content
Defamatory, libelous, threatening or other material that advocates against any individual or group
The sale of body parts or bodily fluids
The sale of hazardous substances
Political, religious or charitable organizations, issues or causes
The sale of tobacco and tobacco-related products
Hacking, surveillance, interception or de-scrambling equipment
The sale (or facilitated sale) of prescription drugs
The sale of counterfeit or stolen items
The sale of government IDs or police items
The sale of alcoholic beverages
The sale of products from any of the following countries: The Balkans, Burma (Myanmar), Cuba, Iran, Iraq, Liberia, Libya, North Korea, The Sudan, Syria or Zimbabwe

The last point is interesting. Don’t you think?