Looks like the low YPN payouts we reported yesterday was a temporary bug and has been fixed. YahooSarah replied to the DP thread stating;
All,Just want to clarify a couple of things here. First and foremost, please know that this is absolutely not a result of a change in payout structure. Advertisers did not pay the same amount as usual per click -- the code launch I mentioned earlier today affected advertiser CPCs, so the earnings you've seen are based on what advertisers were actually charged by Yahoo!.
Many of you have already seen improvements today, and should continue to see more improvements over the next 1-2 days. We expect the systems to be fully stabilized and upgraded by Wednesday.
Hope this is helpful - thanks again for your patience.
YahooSarah
The forum folks love the direct communication on Yahoo!'s part. And it is great! If after Wednesday, your earnings to not level out, then I would report back at the DigitalPoint thread.