It worked for a while, but it doesn't work anymore. Seriously, stop making the clones for profit. I believe making a flappy clone at school or as a programming excercise is a good thing. If you are looking for a first game to learn some new engine, go ahead. Flappy Bird is an excellent choice. But do not expect to make money from it.
On a side note, some people are very creative when using the flappy bird craze. Especially now, when Dong Nguyen announced he's going to release a new, better version of his game. Here's an excellent example how to use the phrase "new flappy bird" to attract more attention to the game called 2048. You will see this link when googling fo the said phrase. And the first paragraph of the article even mentions another famous game: "This latest addictive gaming sensation [2048] is like Candy Crush for math geeks." SEO FTW.
