question...again lol. so this app has changed so much do i have to tag ppl in a post or is it like fb and automatically…

question...again lol. so this app has changed so much do i have to tag ppl in a post or is it like fb and automatically send notification to that person. like if i post and someone commoents do i have to tag them? or if i comment to someone elses will it notify me if someone comments on theirs?