This is bound to be annoying if you're used to Explore being an unsullied space. However, it's not at all shocking that Instagram would go this route. While regular ads are based more on your individual tastes, Explore ads can revolve around trends -- if there's a hot meme, marketers can seize the moment. That's good for both their bottom line and Instagram's, and they're not about to turn down the opportunity when more than half of users visit Explore at least once a month.