Wombat I don't think it should be added to the core, but as an extension.
It is part of the Subscriptions extension.
Wombat What's next? Blocking a user's profile? Blocking a post? Blocking a user's pm message? Blocking them from online lists? Blocking them from viewing your profile?
Yes, absolutely. Several of these are very useful features for some communities where certain members have inevitable, unresolvable conflicts. They're not on our roadmap for the time being, but I have no doubt others will create them.
Wombat If a person really has to 'block' a thread on a forum, I worry about their social life that's a personal problem not a github pull request.
(Looks like you edited your post as I was quoting. I've updated the quote to reflect.)
Careful now, you're stepping into dangerous territory. You are being extremely ignorant about the reasons someone may wish to ignore a thread. What if I am just not interested in having the frequent updates to the "Word Association Game" cluttering up my discussion list?
In any case, this thread is to discuss implementation of the feature, not its merits. Any subsequent posts debating the latter will be deleted.