berto - 7:06 pm on Jan 15, 2006 (gmt 0)

Second and third content ads not appearing on a page is an old and long-known phenomenon.

What appears to be new is link units failing to appear. I have pages, otherwise very profitable pages, where the link units are failing to show, while content ads--later in the HTML code sequence--are showing.

That is, the first ad on the page--the link unit--is failing to display, while subsequent content ads are showing.

It is all the more mysterious because there is plenty of content on these pages. Link units on these pages displayed unfailingly a month or two ago before the recently announced link unit "improvements". And fully complemented link units were and still are showing consistently on similar pages covering nearly the same topic.

These now-you-see-it-now-you-don't link units are exceedingly annoying.