A method, system, and computer program product for operating a collaborative bookmarking system (CBS). A request is received from a client for a universal resource locator (URL) associated with an identifier, wherein the URL and the identifier make up a bookmark which has been previously shared with a community by a user. An alternative candidate URL for the requested URL is located, wherein the alternative candidate URL has previously been suggested to the CBS by the user as a replacement for an original URL. Client validation, by the client, of the alternative candidate URL is requested and received. The validated alternative candidate URL is associated with the identifier as part of the bookmark in place of the requested URL.