The best ideas are often old ideas reworked into something new. I recently read an article about The Republic of Letters, which was a prototypical social network of written correspondence between the brilliant intellectuals of the seventeenth and eighteenth centuries.
This 'social network' boasted members like Voltaire, Rousseau, Newton, Leibniz, Franklin, Diderot, and a whole bunch of other smart people who shaped enlightenment thinking, and it was a channel of communication that allowed each of these individuals to comment on their peer's work and ideas in a time when communication was much slower and distances were much longer than today.
Now we have things like Facebook and Twitter that help us communicate with other people and engage with/comment on their ideas, and of course, it's easy to think of this kind of media as 'new' — as if they were invented in a vacuum. But really, these things are just new versions of an old idea: a network of correspondence between people seeking connection and engagement to shape what's immediate and important in their lives.
So if you're looking for a new idea and struggling to find one, maybe what you're looking for actually isn't a new idea at all. Maybe it's an old idea that's waiting to be transformed, reworked, or improved upon.