The document discusses various continua of considerations for blended learning, including: the balance between sail ships and steam ships in 1851 America; the relationship between teacher and student motivation and roles; whether learning takes place in school vs other places or alone vs socially; the teacher's role in content and responsibilities for students; characteristics of online course content like authority, curriculum match, skill development, engagement, assessment, and portability; and the technology used like desktop vs pocket-sized devices.