A method, system and computer program product for ensuring that the tags accurately describe a resource referenced by a bookmark in a collaborative bookmarking system. A user bookmarking an Internet resource that is referenced by a bookmark is detected. The user provides a description of the bookmark in the form of metadata, which includes tags, to be associated with the bookmark. The Internet resource is analyzed to determine its meaning. A second user bookmarking the same Internet resource that is referenced by the bookmark is detected. The second user provides a description of the bookmark in the form of metadata, which includes tags. The Internet resource is analyzed a second time to determine its meaning If the relatedness of these meanings is beyond a threshold limit, then the original bookmark metadata is invalidated and the invalidated tags are replaced with the tags provided by the second user.