When reading an editorial in The New York Times I found this "tip" at the end of the article: -
"To find reference information about the words used in this article, hold down the ALT key and click on any word, phrase or name. A new window will open with a dictionary definition or encyclopedia entry. "
I tried it and it works. This is my first experience with this capability and for now it seems to be peculiar to the Times editorial. How far will this capability spread? What will it take to make it universally available? I consider this an amazing feature, worthy of at least one big WOW!