Is it just me? I'd never heard of this word and then suddenly it's everywhere.
People talk about extrapolating information on threads on MN, and in meetings I'm bombarded with showers of the blessed word.
I understand it means "Extend the application of (a method or conclusion, esp. one based on statistics) to an unknown situation by assuming that existing trends will continue or similar methods will be applicable."
But many people seem to use it as a fancier version of "extract".