Kek is a common term used on 2b2t. The term is another way to say "lol". The term originates from World of Warcraft as when alliances message hordes, they are not supposed to understand each other as the messages are in different fictional languages. The term "lol" translates into "kek" between the two and so the word began to spread around the internet, appearing in memes and several message boards. Eventually, it spread to 2b2t and people have been using kek ever since.