I'm making a stand that every planner has to wikichain at least once a week.
You know, that time killing device whereby you go to Wikipedia to look at Virgin Atlantic and somehow 3 hours later find yourself reading about Erasure. [ Something like, you followed a link of "aircraft", then from there you clicked "flying picket", then the band "flying pickets, then "only you", then Yazoo, then "Vince Clarke", then "Erasure".]
The big thing for me is, that not only is a great teacher of how things tie together, but it serves a more fundamental purpose being able to see objects and events as a whole; which makes it easier to see how objects have a meaning for people, how they are relevant in their lives, and sometimes how companies completely miss the point.
Everyone do something for me. Go to Wikipedia. Start on the article "advertising", then click on a link within that article. 10 articles later tell me where you end up. Thanks :)