Finally the flag module got released - a really useful module and known as the successor of the previous "Views bookmarks" module. The project page says:
Flag is a flexible flagging system that is completely customizable by the administrator. Using this module, the site administrator can provide any number of flags for nodes, comments, or users. Some possibilities include bookmarks, marking important, friends, or flag as offensive. With extensive views integration, you can create custom lists of popular content or keep tabs on important content.But even better the 1.0 (and 1.1) release is shipping with extensive rules integration. So once you have installed both modules you can create flags and use rules to add some behaviour to them, e.g. you can react once a flag is "flagged" or "unflagged" and send mail to the content node's author, unpublish it, change the content's access settings - or whatever you have actions and conditions for! Then the module also provides actions for flagging or unflagging flags, checking the flag count in case of global flags and even to "Trim flags", which allows you to restrict the number of flagged items. This way you could even create simple queues. Of course there also conditions to check whether a flag is flagged and again in case of a global flag you can check the flagging count. Amazing! Also the flag module comes with a bunch of useful settings, so you can configure the flag to have a confirmation form or to just work with an AJAX link. Together with the powerful rules integration one could implement a lot of useful stuff - want a custom link with custom permissions to publish a content node? Just use a flag and an appropriate rule!