Is low ad inventory the basic reason for YPN's bad targeting?

few advertisers => bad ad matching

[berto]

Is the limited number of advertisers signed up with Yahoo! the underlying reason for YPN's bad ad targeting?

So, for example, if there are only two advertisers in one narrow niche, in a skyscraper ad unit those two advertisers would show, along with two or three other off-target or RON ads filling the remainder of the ad unit slots.

Adsense's ad targeting may be better simply because Google has so many more advertisers in its stable.

My guess is that Yahoo! is doing everything in its power to attract new advertisers.

Would anybody care to guess how many more (as a percentage or ratio) advertisers Adsense has than YPN?