In Fall 1992 at Michigan State University, we first offered online homework to one section of an introductory physics course; students received randomized assignments as printouts and entered answers through Telnet sessions, frequently using text terminals. Now, over two decades later, all of our introductory physics courses have significant online components, and students can chose between different formats, including hybrid courses with free online textbook materials, as well as courses that are completely online. What have we learned over the years about which formats are most effective for which students? What are the respective learning outcomes? Which logistical models work best for homework, exams, videos, and textbook materials? What about academic integrity? In my talk, I will reflect on how our courses have been developing over the years, report educational research results, relate anecdotes and experiences, and point out pitfalls that we have encountered.