Their spread so captivated social media that many wondered whether the world was falling for a viral marketing campaign.

这一扩散现象吸引了社交媒体上的关注，以至于许多人都想知道世界是否充斥了这种病毒式营销活动。

Are you getting plenty of referrals and enjoying viral marketing?

您是否获得了大量推荐并享受病毒式营销？

Another way TikTok differs from big American social media apps, which largely grew through word of mouth, is that its expansion didn't happen entirely through the magic of viral marketing.

TikTok与美国大型社交媒体应用的不同之处还在于，它主要是靠口碑传播，并不是完全借助网络营销的魔力。