I signed up for Yahoo Publisher about two months ago I believe and was informed they were not taking on any more beta testers at that time. Then about 5 days ago I received a welcome message to the Yahoo Publisher Network.
Yahoo is waaaay stricter than Google when it comes to partnering with their advertisers. I believe many affiliate oriented sites have a harder time getting approved because major search engines (such as Yahoo and Google) do not necessarily feel affiliate based sites offer "value/content rich content". I'm still trying to get approved for a Google Adsense for Feeds Account and the Yahoo! Search Marketing/Yahoo! Small Business affiliate programs marketed via Commission Junction. Those last two are excellent HIGHLY IDENTIFIABLE services with excellent EPC's and Network Earnings
In retrospect I feel one should first build up a content rich site offering articles, reviews, a blog* and associated resources. Leverage some good link building to gain link popularity, with
LIKE SITES*, and gain that notorious (but overrated) Google PR.
DO NOT PUT ANYTHING ON YOUR SITE THAT PROMPTS PEOPLE TO BUY ANYTHING....YET. With your non commercial oriented site apply for Google Adsense/Adsense for Feeds and the aforementioned premier Yahoo affiliate programs via CJ. Once you have been approved for these programs you can start to add revenue generating programs or contextual based advertising.