I was browsing the Nielsen//Netratings list of top internet advertisers for December 2005 and I noticed that several of the advertisers were also advertisers commonly believed to be Yahoo Publisher Network Run of Network (RON) advertisers as well.
The three I noted included Vonage, the advertiser most commonly associated with RON ads, as well as LowerMyBills and Nextag.
The complete top ten included Vonage, General Motors, LowerMyBills, NexTag.com, United Online, BellSouth, SBC, Dell Computer, Netflix, Inc., Scottrade, Inc. It is also possible that there are more RON advertisers in this list, but doing their advertising under a different brand URL.
It does make me wonder how extensive this advertising was done through the YPN RON ads, although it is well known that these advertisers also use other advertising sources besides YPN, including other Yahoo Search Marketing advertising as well as through Google.
You can download the complete report from Nielsen//NetRatings in PDF format here.