Provide subscribe and unsubsribe checkbox / radio button for forum threads

One of the things I find most useful at drupal.org is the user Dashboard and 'Your Posts'. However, the 'Your Posts' section can get overstuffed with forum threads that 'refuse to die' or get updated with 'subscribe' comments. I'd like to be able to unsubscribe to some forum threads without polluting the them with an 'unsubscribe' post. Likewise, some forum threads have an excessive amount of 'subscribe' comments.
It would be good to have a checkbox / radio button option for subscribing or unsubscribing to forum threads.