CULTURAS IN VITRO - Canadian bestseller lists are bunk: "We are in the Dark Ages," says publisher Kim McArthur, who has been sitting on an industry-wide committee studying the way suppliers and retailers in other industries and in other countries track sales and exchange electronic data. "Have you noticed how when a movie opens, we know how many people went the first weekend?", she asks rhetorically. "What we do in books is to say, 'Let's hold our finger up in the air and guess how many people bought our books over the weekend.' That would never, ever happen in a grocery store, in the movies or in the record industry."