I remember when Internet Killed the Video Star first came out in 2000, I thought "that's a cute parody, but that will never happen". Now, MTV doesn't play music videos any more while YouTube is full of music videos, and even makes successes out of some of the indie bands who post their videos on the site!
Then, when the first tv broadcasts started coming out I thought that the internet would always be a poor way to watch television shows, and now I'm thinking about canceling my cable and just watching the shows I like through Hulu.
I'm getting the same feeling of "that will never happen" when I hear people talk about how most new entertainment will be interactive in the future. I can't help but wonder if I'm underestimating technology again.