@Loial, there are actually two new tabs on our profiles. As I understand it, "Thread Tags" lists when we've mentioned someone else; "Mentions" lists when they've mentioned us.

After I submit this, I'll check my profile to make sure they work the way I think they do.

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Edited to add: It took a few minutes but now both taggings, the one where DocJohn tagged me and the one where I tagged Loial, show up under my Notifications tab. I still don't see the latter one anywhere on Loial's profile.