Changing the way we use the Internet
In the 1980s, I was a "find useful stuff at public FTP sites" resource at SAIC. I spent time maintaining lists of useful FTP sites and what they contained so I could help people quickly find stuff. Gopher was a step up. Good search engines were a huge improvement for finding stuff on the web.
Now I find myself mostly depending on what interesting people recommend. Even though I am a techie and don't represent a typical Web user, I still think that the trend of using social media to find interesting (and even useful!) material is widespread. It will be interesting to see how the major web companies like Google, Amazon, Microsoft, Yahoo, etc. perform financially in the future because it seems very difficult to predict new disruptive technologies that will capture peoples attention and interest.