If I may add another possible benefit of what "ignore a topic" may offer, sometimes we want to leave a topic we're previously engaged on, either because the topic no longer interests us or it has turned into a meaningless discussion filled with spam posts. I am not sure there is currently a way to "remove" these threads from our "show new replies" page. The ignore a topic button would be a nice thing if it means it will remove those threads from my new replies page.

I'm busy helping theymos with something that might keep me occupied for a while, and then after that I'd like to send him the 2FA patch that I've been talking about for months. Once those two things are done, I'll see about this proposal; haven't thought too deeply about it, but it seems like a good idea to me, and I think it's something that I would personally use.