Business Plan vs. Business Model

Just got back from the USASBE conference, and kept hearing talk there about how Business Plans are "out," being taken over by Business Modeling. So I did what any good blogger does and ran the two terms through Google Ngram. Sure enough, as you can see no one talked much about either until around 1970, then use of the term "business plan" grew steadily until around 2002, when it leveled off. Meanwhile, Use of the term "Business Model" really took off around 1997 (perhaps not coincidentally, this is the year that Clayton Christensen published The Innovator's Dilemma, as Christensen has become a vocal advocate of business model innovation). Now the frequency of use for the two terms has converged. I've been poking around in the business modeling literature for the past few months, and I'm still not sure that the two terms have substantially different meanings, but I'm open to being convinced.