When you are searching for some topic and arrived to some webpage. After going through that webpage, you find that you can add some more useful information on that topic which will help others who are looking for the same information.
What if everyone had an easy way of sharing their insights with you about any page on the web? What if you could add your own insights for others who are passing through?
Now you can. Google announced Sidewiki, which allows you to contribute helpful information next to any webpage. Google Sidewiki appears as a browser sidebar, where you can read and write entries along the side of the page.
Rather than showing most recent entries first, it shows most relevant entries first. Google ranks Sidewiki entries using an algorithm that promotes the most useful, high-quality entries in real-time. It will also take your entry about the current page and show it next to webpages that contain the same snippet of text. For example, an entry on a speech by President Obama will appear on all webpages that include the same quote.
It also brings in relevant posts from blogs and other sources that talk about the current page so that you can discover their insights more easily, right next to the page they refer to.
Google Sidewiki is also available as a feature of Google Toolbar (for Firefox and Internet Explorer) and it will be soon available in Google Chrome and elsewhere too.
For developers, Sidewiki API are available to let anyone work freely with the content that's created in Sidewiki.