Mostly I agree with Worldwalker. In this case, only somewhat.
If other media interferes with my leisure reading, I agree. But sometimes other media is needed or desired.
I've read, and re-read, W. E. B. Griffin's WWII books. But sometimes you'll hit something that you don't know.
Everybody that knows what a Brewster Buffalo is, raise your hand.
Not too many I see.
Brewster Buffalo
Need more info on the Corregidor tunnels"
Narwhal, anyone?
Those examples would be ok in some ebooks and especially in a "text" ebook.