There is no specific answer to this question because we can never know what can happen in just a few months or years. Let’s take for example the now defunct Friendster. It was so famous several years ago and nobody thought that it was going to reach its end after the introduction of Facebook. Although Friendster was at the top of the game before, things just dramatically changed and we were all left with the news that Friendster was officially shutting down.
Now, looking at the question as to what will be the next Facebook or Google, no one knows what exact application can become as famous as Facebook and Google. Would it be Instagram or Twitter? We can’t say for sure, but Facebook has a chance to become the next Google and it even has the chance to surpass Google in the future. It may or may not happen.