This is one of the problems with the aggregation of listing information. As professionals, we spend a lot of time addressing this kind of confusing discrepancy. One of the first things I look at when a new listing comes on the market is who listed it. That can tell me a lot about the accuracy of the listing information, why the pictures show a beach when the house is more than a walk to any water, and why the price is so.
Finding an experienced, local broker, or agent, to help you learn about the area and properties you are interested in can save you endless confusion, wasted hours, and can definately help you not miss a good purchase.
You might call the old listing agent and see if it is still for sale and what she says is the reason for the difference. Millennium Realty (508) 478-7756 Listing Agent: Judy Leonelli (508) 377-9190
Another thought to add to Judy's answer: If an appraiser and the assessor disagree, that indicates a needed close look at any permits that may or may not have been completed at town hall for additions or improvements to the property. If work has been done without permits, then why, and who did it, and was it to code, etc.... more