Framingham, Mass.—IDG World Expo said it has canceled its East Coast Macworld Conference & Expo, which it has held in Boston in the summer for the last 20 years. The company will continue to hold its flagship Macworld Conference & Expo in January in San Francisco. “The San Francisco event has always been our flagship event,” said Mike Sponseller, spokesman for IDG. The Boston event typically attracts about 8,000 attendees; the San Francisco show attracted 36,000 attendees in January. Sponseller said the company will focus its resources on expanding the event in San Francisco.