IMO, Some competition is going to benefit Adsense publishers because Google has to worry about losing publisers to a real competitor. http://news.com.com/Yahoo+seeks+to+expand+in+Google+territory/2100-1024_3-5609792.html?tag=nefd.lede
Honestly, I think PPC publishing is dieing. Even with some competition, the average adsense user won't make more than a few dollars a day. Is that really worth sending the amount of visitors that it took away from your site? I think not... I've been looking for a while for a decent, free alternative to PPC publishing, and I think I've found it. I've started a blog about it, for anyone who's interested: shadowmarketer.blogspot.com
You have a good point there ShadowMaker. Adsense has been going down hill for me for awhile now. It really should be worth more if you're going to send a visiter away. I'm off to read your blog. -all4one