His article "How David beats Goliath" asserted that smaller, weaker competitors beat their stronger, better equipped opponents by dramatically changing or breaking the rules of engagement.
http://www.newyorker.com/reporting/2009/05/11/090511fa_fact_...
One of the examples was average or weak high school basketball teams using a full court press technique to defeat the best teams in the league. The other example is Lawrence of Arabia defeating the Ottomans at Aqaba. In letters which were published later that summer, readers pointed out that a full court press is used by many "Goliath" teams, and that the Ottomans were actually the underdogs since Lawrence of Arabia had the support of the British Empire.
I'm not a basketball person or a historian, so maybe the letters were off, but the New Yorker did publish them, and they certainly did make me question the article which I had so enjoyed a month before.
The letters in question:
http://www.newyorker.com/magazine/letters/2009/06/08/090608m...
http://www.newyorker.com/magazine/letters/2009/06/08/090608m...
Maureen Tcacik wrote about him in The Nation, and was generally critical of his style and methods, but also a little admiring. Interesting read.
http://www.thenation.com/article/gladwell-dummies
And just for HN, I dug this up because it made me laugh: http://www.nytimes.com/2009/11/15/books/review/Pinker-t.html...
"He provides misleading definitions of “homology,” “sagittal plane” and “power law” and quotes an expert speaking about an “igon value” (that’s eigenvalue, a basic concept in linear algebra). In the spirit of Gladwell, who likes to give portentous names to his aperçus, I will call this the Igon Value Problem: when a writer’s education on a topic consists in interviewing an expert, he is apt to offer generalizations that are banal, obtuse or flat wrong. "
In the cases where he is correct (if only by dumb luck,) it's still not helpful since you don't know which ones they are without doing the legwork yourself.
It is intellectual slop, ideally suited to the best-seller list of a major sunday newspaper, but it is not true or even some approximation of it. If that's how you like your social science, then have a bowl of Gladwell.
For other people's takes on him, try:
http://news.ycombinator.com/item?id=1063576
http://philip.greenspun.com/flying/foreign-airline-safety
http://blog.jgc.org/2010/06/how-to-write-malcolm-gladwell.ht...
http://www.fastcompany.com/magazine/122/is-the-tipping-point...
http://www.vanityfair.com/culture/features/2009/12/gladwell-...