The last time I used facebook was, maybe 3 or 4 years ago, can't fully remember, so my statement here might be outdated, but the last time I used facebook, the only kind of "promotion" you'd get is if you "boosted" posts with advertising. There was nearly no organic reach at all even when using hashtags from memory. I'm not sure what it's like now, but I don't think it's like Twitter. Others will no doubt have better up to date answers than me.