Looks like Yahoo! Publisher Network is experimenting with its contextual network to improve ad delivery. Conflicting reports have come from DigitalPoint Forums alternately saying that the duplicacy of ads has improved or worsened. One of the members reported that:
YPN has improved one aspect of their ad delivery — ads no longer repeat ad nauseam across your ad blocks on a given page. Before, depending on how many ad blocks you had on a given page, the same ad that showed up in the #1 ad queue position would show up in all the #1 ad queue position of all your ad blocks on that page. Not anymore. I'm no longer seeing repeated ads across the ad blocks.
Subsequently the same user edited the post to say:
I just checked my site an hour later after making the thread — yup, the ads are repeating themselves once more. LMAO. I guess they're "working on it" still.
More positive feedbacks came from other users.
I noticed this improving for the past week. It seems to be doing really well though. Looks like they are making their way out of the beta one step at a time.
has 3 bocks of 5 ads each and they are showing 15 different ads. Which is very good improvement.
There is also a post at YPN blog stating the same.
In response to your concerns, we recently did some fine tuning. Today, we’re pleased to announce the launch of an enhancement that should improve the number of unique ads shown on pages with more than one ad unit. This enhancement applies to all types of ads, but impacts only our self-service publishers (i.e., most of you).
Good news all round. But as many would agree, Yahoo! has along way to go if it wants to compete with Google.