I worry about that, too, but I think it's unlikely to happen, because Bitcoin will stabilize eventually. But it first needs to become so big (think $100 billion - $1 trillion here) that every single transaction affects the value in a very small way, and any top HN or Reddit article about it has an almost insignificant effect on its value.

I do believe that will happen eventually, but it's too early right now. Bitcoin works by the law of numbers - after all it's all numbers and math. When its tiny in value, its growth can be very high. When it's already huge, the growth will slow down a lot.