Not saying this is the case in your example, but take the Mariah Carey post: it wouldn't be hard for someone to buy up legit-looking accounts and make a bunch of posts about Mariah Carey (or whatever person/thing) to refresh everyone's memory about the topic in advance of some new concert or movie in a few months.

Again, it's not necessarily the case in your screenshot, but at the same time, how do we tell for sure?