YPN is the second biggest pay per click advertising network after Google Adsense.
It is characterized by the following features:
* At this point, it is only available to US publishers.
* YPN lets you choose ad categories to show on your site, it can be used in either custom mode or contextual mode. There are 19 categories for you to choose, and you will get much better ads if you site falls within these defined categories.
* YPN publishers have the option to be paid with PayPal.
* YPN allows ads in RSS feeds for all publishers unlike AdSense which selectively choose publishers.
* Do not use YPN and AdSense on the same pages. Their terms of use prevent co-existence on the same page at the same time.
