Google is getting to know you a little better in order to send you ads you'll more likely like.

The Mountain-View, Calif.-based internet company is starting to gather information about the websites people visit using an individual web browser in order to target ads to their interests, Google has announced on its blog.

"By making ads more relevant, and improving the connection between advertisers and our users, we can create more value for everyone," the company said. "Users get more useful ads, and these more relevant ads generate higher returns for advertisers and publishers."

"Interest-based" advertising was launched Wednesday as a beta test on third-party sites that carry Google ads, as well as the YouTube video site that Google owns.

Demand from partners

The blog entry called advertising "the lifeblood of the digital economy" and said Google's advertising and publishing partners have been asking it for a long time to offer interest-based advertising, which is already used by some other companies.

Google's system will be able to infer users' interests based on the sites they visit, which will be associated with their browsers using a tracking file called a "cookie."

What is a cookie?

A cookie is a text file that can collect and store information about you on the hard drive of your computer, such as what web pages you've visited, your custom user preferences for a given site or the items in your "shopping cart" for a particular online store. Many sites use cookies as a way to track visitor information. Cookies are stored to help sites speed future access and customize information for you. Since a cookie "remembers" your preferences, it can save you time. But some people consider the use of cookies an invasion of privacy.

For example, each time a user visits an adventure travel site that carries Google advertising, a cookie will be placed in the browser. If the user visits many such sites, he or she will be flagged as someone with a strong interest in adventure travel and more ads for activities like hiking trips to Patagonia or African safaris will show up in the browser even when:

  • The user is on a Google partner site that doesn't involve adventure travel.
  • When someone else is using the browser.

"This kind of tailored advertising does raise questions about user choice and privacy — questions the whole online ad industry has a responsibility to answer," Google acknowledged, adding that other companies that provide interest-based advertising deal with this in different ways.

Won't add 'sensitive' interest categories

However, the company promised that:

  • It will not collect the user's name or any other personal information.
  • It will not use sensitive interest categories such as those based on race, religion, sexual orientation, health or "sensitive financial categories."
  • Users will be able to view, delete and add interest categories associated with their browser.
  • Users can opt not to accept advertising cookies from Google partners.

In addition, users will be able to clear the cookies used by Google's targeted advertising the way they usually clear cookies from their browser.

Until now, Google's ads have been targeted based only on the site that the user is currently viewing. For example, the user would receive adventure travel ads only while on an adventure travel site or reading an email about adventure travel.

However, other companies have been offering personalized online advertising for some time. For example, social networking sites MySpace and Facebook have targeted ads to individual users based on their profiles since 2007, and retail sites such as Amazon and iTunes regularly recommend books and music to their users based on their past purchases.

Tim Richardson, who teaches e-commerce at Seneca College and the University of Toronto, said advertisers are increasingly turning to more targeted advertising because it's more efficient than mass advertising.

"If it's more targeted, then they're going to increase their success rate," he said.

So far, he said, it looks like Google has taken the right steps to be transparent and safeguard users' privacy. When people feel their privacy is being invaded, they get spooked, he added.

"What Google doesn't want is for people to think it's Big Brother."

However, he said that companies who advertise with Google will want evidence that the more targeted approach is working and Google may change its approach in the future.