I really dig this guy because he's on the ball about changing technologies and their impact on language-learning. Anyway, this is the most recent general writing of his I've found on the topic, and it's accessible, so: http://www.gresham.ac.uk/event.asp?Page … ventId=851
My very short summary: Dictionaries are good but they won't tell you everything about words, so google them, google image them, search for them in corpora. Check out this website http://www.worldwidewords.org/index.htm. Also, someday we might have virtual reality dictionaries that let you touch and smell things.