The drop in cholesterol is thought to be because of changes in hens' diets, the way the animals are bred or other factors. (summarized from USA Today)

Here's what I thought hearing this news story, "If chickens are given better feed due to new regulations and there eggs are proven to be healthier, what if you only feed them really good organic food and let them get out into the sun (when they get sunlight they have higher levels of vitamin D, they also, according to my local farmer at our farmer's market don't need to be debeaked then)?"  Well if you buy organic eggs, that's what you get.  They often feed them a diet high in omega 3 ALA (plant derived), and they get sun which means more vitamin D, not to mention probably less prone to disease due to better sanitary conditions (watch a clip from the documentory Food INC here to see what I mean).  I think this helps show that all eggs are not the same, and that our food is not as nutritious as it could be.