celgins - 11:22 pm on Feb 27, 2010 (gmt 0)
I've never done any in-depth tests for split articles, but most of my Adsense clicks occur on pages containing the full article.
Weird things tend to happen on page 2.
My observation centers around how users navigate article pages. I have noticed that some users reach the end of page 1, and don't bother going to page 2--even when it's clearly marked that additional pages follow.
For users who click and read additional pages, they seem to be truly interested in the topic, and less interested in ads. However, there is a really good chance that users who finish an article that interests them, are looking for more good content within the site and may click an ad that interests them.