Google is further expanding its advertising by placing contextual ads in XML-based syndication feeds. The company has begun testing the use of its ads in RSS (Really Simple Syndication) feeds, and is encouraging sites to take part in the tests.

"Over the next few weeks, part of the trial is to tune it and make sure the ads are not intrusive," said McLaws, president and chief software architect at Interscape Technologies Inc.

Google has declined to comment on how exactly the ads are implemented in feeds, and said that their approach may change as times goes on.