Tagging a username shows up in the activity log. Reblogs you won’t know with the tag system below. I think the username tag link was created to combat the tag issue.
umm but
just replying does that too
(the tags are an xkit thing, but including the first few words of the reply is not)
The replied/reblog notification that shows on your dash is only if you’re lucky to see it though. Also, if you’re not following the person you wouldn’t have any idea unless they tagged you in the body. Even if you were following them, and they reblogged something and put you in the tags below, you might not see them (though maybe not right away if you’re using XKit).
but i’m not following you and i saw it, because you reblogged my post
and why are you more likely to be lucky enough to see an @ than a reblog??