I just completed a write-up for class that summarizes a couple of articles on online mapping applications.  While doing my research, I found that while information on the subject was plentiful, the amount that was easily available was few & far between, so I'm posting it here in hopes that it may help someone in the future.  It's a quick overview of what goes into an online mapping application and a look at how companies are starting to ditch Google Maps in favor of open source alternatives like OpenLayers.