I'm not American, but noticed a strong difference in memes leading up to each of the last three elections. I have no numbers, but I noticed that there seemed to be an unnatural amount of pro-Obama memes that spread before the '08 and '12 elections. They were high quality and spread fast. In my (largely liberal/progressive) social media bubble, I noticed very few pro-Trump memes before the the '16 elections, but huge numbers of anti-Hillary ones.

As I said I don't have numbers and I don't know what kind of effect memes actually have, as they are largely consumed by young non-voters, but it's not secret that Obama had a very active meme-team and it makes sense for Trump to have followed the strategy.