Ah, young love. The butterflies. The starry-eyed obsession. The trembling first kiss. The dramatic increase and then sudden drop-off in Facebook posts. Tale as old as time, as a new blog post from Facebook revealed today. As one of Facebook’s analysts Carlos Diuk says: “During the 100 days before the relationship starts, we observe a slow but steady increase in the number of timeline posts shared between the future couple. When the relationship starts (“day 0″), posts begin to decrease.” Hopefully, that happens because the couple is spending more time together and don’t need Facebook anymore. Of course, that “Day 0” of a relationship begins a sudden, aggressive surge in the couple’s new joint Netflix account …