Replying to 'Subscribe to Thread'

I think this would be a good way to keep the useful (yet useless) action of claiming 'threads' to a minimum. This would help keep the posts in a particular thread more to the point, yet those that do not have something to add could still remain current with the thread content. The subscribed threads could simply be added to the 'my threads' list, meaning that the simple addition of a subscription option next to 'reply' button would be all that is needed. Good idea?