Third Voice was a web annotation browser plug-in launched in 1999 by a company of the same name.
Initially when websites were visited there was often little content available from other Third Voice users.
The product soon received much criticism by website owners claiming they were trying to externalize discussion.
The White House website was annotated with topical jokes.
Further issues arose when spammers began to leverage the product, and increased issues arose when cross-site scripting security vulnerabilities were exploited in the product.