PropertyShark.com
In geek-speak "information asymmetry" is a problem that crops up, for example, when you buy a house. The seller knows more about the house than the buyer and thus has an unfair advantage in the deal — though perhaps not for long. PropertyShark.com is a free service that culls an incredible amount of data for houses in the big, coastal population centers, plus Texas. The PropertyShark database, searchable by address, tracks price history, comparables, tax-roll information, owner names, demographic information, flood and fire maps and more. A subscription buys even more information, including lists of foreclosure auctions and pre-foreclosure notices — even phone numbers of property owners. By the time you make that call, you may know more than he does.