sit2510 - 2:44 am on May 31, 2006 (gmt 0)

>>> My site's pages indexed in Yahoo have been dropping by 2 to 5 pages a day since 3 weeks ago.

I notice the same with one of my sites with very weak inbound links. It started with around 150, dropped to 90 during the past few weeks, but now site search shows about 220. Overall pages of the site are around 1,000. So no major alarm about penalty or banned.

You may want to refer to MC's coiled word of "crawl fringe". Though G and Y are different engines, the symptom seems to be very similar in concept but different in formula.