. >> reporter: shoppers like cynthia spencer are concerned when they hear google has a new tool for tracking consumer habits but google says it's not what some people might think. the company explains it this way. google will look at one month of online advertising and one month of in-store sales to help retailers see if their advertising is driving shop her -- shoppers to physical stores. this tech analyst doesn't like the sound of it. >> it's following us from the internet to the brick and mortar store, even if it's aggregate and encrypted and anonymized, it's still in people's minds is something they're not comfortable with. >> reporter: a marketing professor at santa clara university and guest professor at google doesn't see it that way. he says it's no different than what the u.s. census bureau does. >> you can go online and just type the zip code and you will get the demographics of the people here. that is based on individual census data but the census bureau never releases that individual census data. >> reporter: google released a statement that reads, in part, we developed a new cu