What is Google Sidewiki?
Google Sidewiki was a social annotation web browser extension launched by Google in 2009. It enabled users to make comments and annotations alongside any web page they were viewing, allowing them to share notes and have discussions about online information and content.
Sidewiki worked by displaying these user-generated notes and annotations in a sidebar next to the web page content. The comments would highlight specific parts of the page based on what the commenter selected. This allowed collaborative annotation functionality for information on websites.
The goal of Sidewiki was to improve sharing of knowledge and evaluations of content across the web. Users could see who else left comments, carry on discussions, and benefit from the annotations left by others accessing the same pages. The service was controversial due to the lack of website owner control and consent over these public third-party contributions.
After launching in 2009, use of Sidewiki remained limited. Google decided to discontinue the service in September 2011, ceasing support and development after about two years. The core functionality of publicly sharing annotations alongside web content has still not become mainstream, although services like Genius and Hypothes.is have continued innovating in the collaborative annotation space.