Google is going after local businesses in a big way. It is promoting Google Places any time someone does a local search, it tried to buy Groupon for $6 billion, and it put star exec Marissa Mayer in charge of local products . Since the middle of December, it's been running a $100 million marketing promotion aimed at small and medium-sized businesses to try to get them to sign up for AdWords. Small businesses that sign up by December 31 have until mid-February to spend $100 on AdWords, after which they will be given another $100 credit. The promotion is good for "the first one million businesses only." If one million businesses sign up and spend that $100 the total value of the campaign will be $100 million. Of course, the campaign won't really cost Google anything. It is spending $100 to acquire these small local business as new customers. It has offered similar promotions in the past. But Google's efforts go beyond offering these credits.