The Google AdSense Mystery: Revisited

Picture credit: http://www.google.fr
I have some questions regarding my AdSense reports. Whoa, let me back up a bit. I use Google AdSense, primarily to familiarize myself with context-sensitive ad networks. I place AdSense text ads on my blog, a discussion board, and a newsletter that gets sent out from time to time. Check this report out of advertising performance over the last few months:

Date range	Page Views	Clicks	Revenue
Dec 1 - Dec 22, 2004	282,504	83	$23.73
Jan 1 - Jan 22, 2005	328,126	131	$32.48
Feb 1 - Feb 22, 2005	318,908	80	$12.95
Mar 1 - Mar 22, 2005	379,831	474	$63.81
Apr 1 - Apr 22, 2005	280,116	544	$60.10
May 1 - May 22, 2005	281,606	454	$55.48
June 1 - June 22, 2005	228,743	307	$36.94

Okay, so here are my questions:

1) What in the name of Rowdy Roddy Piper caused the "click-through explosion" between 2/05 and 3/05?
2) What in the heck happened to my traffic in June?
3) And what ever happened to Marie Osmond?

In all seriousness, I really wonder about #1. Were my astounding improvements in click-through typical for most Google AdSense outlets? If so, it's no wonder Google had breakout earnings last quarter.

And is my drop-off in click-through percentage typical for the Google network? And, if so, what are the implications for Google's results this quarter?