It all started with this series of articles, La Macaronicité, published here in December 2007.

La Macaronicité 1: an introduction to the macaron.
La Macaronicité 2: basic technique and simple macaron recipe.
La Macaronicité 3: the more reliable macaron recipe and a few tips.
La Macaronicité 4: fillings, flavours, frippery.
La Macaronicité 5: Macawrongs and macarights, macarons day and night.

Many further articles have mentioned various aspects of macarons. You can view all by browsing the category macarons here. Or you can start by reading some review articles:

Sydney's macarons, Adriano Zumbo, and a few other eating observations.
The macarons of Paris — 2008 review.
Melbourne's not so great macarons, plus rubbish in Epicure.