Look at the geographical breakdown in Google insights for search and you will see that there is more interest in "memes" in Brazil than anywhere else in the world. The geographic distribution for the term "meme" looks much more reasonable. At first I wondered if "memes" was a native Spanish word - the way that "meme" is in French or Turkish. However, Google insights for search gives you the details of what is being searched for. So far, I see no evidence for the idea that these are anything other than genuine searches for memes. It looks as though youth culture in the Spanish world really, really likes internet memes - or "memes da net" as they seem to be called.
The Spanish Wikipedia page on memes is here with an English translation here. Why is "memes" affected more than "meme"? I think that probably has something to do with Spanish grammar. For example "The Meme Machine" translates into Spanish as: "La máquina de los memes".
Me Gusta is probably one of the most famous internet memes to come out of the Spanish-speaking world.
Jesús Mosterín appears to be a leading Spanish philosopher who has embraced memes.
The Spanish seem to go in for meme cartoons - memes tirinhas they call them.
They also seem to be going in for meme apparel - for example havaianas memes (illustrated here).