Daily post frequency rose by 36 percent on Facebook and by 14 percent on Instagram, while slipping by 2 percent on Twitter.

Instagram posted the highest follower growth among the three social networks in 2015, but it peaked in February and began trending downward, while Facebook and Twitter were more stable.

Instagram topped Facebook and Twitter in terms of engagement rate, and brand with the smallest followings (1,000 or fewer) on all three social networks boasted the strongest engagement rates.