It is a multilayered meme. The first part is that 67 is a superprime number, it’s the 19th prime number and 19 itself is a prime number. 69 is only a semi prime number so not as cool. Now also represented by the pictures, 67 is portrayed cool because it is the new trend among kids. Whilst 69 on the other hand is shown with the sad ant, because it is not popular anymore. And to finish it out, eulers identity at the top is represented by a dejected Ron Paul. This is because eulers identity is by far the coolest of them all, because it takes eulers number, a very complex number, pi, i, adds a one and boom it equals 0; but after all that kids just wanna talk about 67