this link. Here are some follow-up posts on the topic:
Matzah/Maror Chart for Rationalists - so that you, too, can have a chart!
The Popularity of Olives - discussing why this paper is so popular and yet hated by some.
Why On Earth Would One Eat A Kezayis? - discussing the strange notion that one should eat a kezayis of matzah on Seder night.
The Riddle of the Giant Kezayis Defense - wondering why many people would not accept that a kezayis is the size of an olive.
Maniacal Dishonesty About Olives - exposing an error-ridden critique that appeared in the journal Dialogue.
It's Krazy Kezayis Time! - discussing the view that one should eat a huge amount of matzah in a very short time in order to fulfill all opinions.
The Kezayis Revolution - A new sefer by Rav Hadar Margolin presents a wealth of evidence for the smaller size of kezayis, as well as testimonials regarding charedi Gedolim who held this way!