• by Laurie Sullivan  @lauriesullivan, September 23, 2009

Google will roll out a new service Wednesday that allows people to post notes alongside Web sites that others using the same application can read. The tool, Sidewiki, will become an add-on feature of the Google Toolbar for Firefox and Internet Explorer. The company is also working on making it available in Google Chrome and elsewhere.

Sidewiki allows people to share travel plans or opinions of experiences. "When researching advice on heart disease prevention or looking for museums to visit in New York City, many others have done the same and could have added their knowledge along the way," writes Sundar Pichai, vice president of product management, and Michal Cierniak, engineering lead for Google Sidewiki, in a blog post.

Sidewiki joins several startups like Kutano that over the years have launched at venture capital trade shows, such as DEMO. The tools also will post notes across multiple sites that have the same content, providing a social aspect to sharing information.

For example, a note about a quote from President Barack Obama would appear on all Web pages that include the same quote. Google also brings in relevant posts from blogs and other sources that talk about the current page so people can discover their insights more easily, right next to the page they refer to, according to Pichai and Cierniak.