Making Assumptions with Your Data
The power of personalization is using the data you have to try to speak more individually to each recipient of a marketing message. The more data points we have, we can build a better picture about each person, and the inferences we make about what they want to hear and buy get more accurate.
One does need to be careful about what inferences you make based on the data you have. If your choices are too broad for what you know, you may miss the mark widely enough to make personalization backfire.
This article by Michael Paladini for The Digital Nirvana looks more closely at this subject:
http://thedigitalnirvana.com/2010/12/targeting-inference-and-missing-the-point/