Look for Google to take a new tack to targeting in its ad network. The word from Susan Wojcicki, a vice president in advertising at the search firm, is that Google will match users' searches based upon what they're currently looking for, not on past behavior. She points out someone monitoring news from a fast-moving hurricane last week, for example, might be more interested this week in checking out sports scores on a favorite hockey team. That's why Google is testing a new service that delivers ads based on a previous search, not simply a specific search term. This …