So, to reiterate, I'm all for active learning as opposed to passive learning... but I do not consider taking a machine-graded quiz to count as interaction. When a student takes a quiz, that is indeed something active on the part of the student: they read each question, decide on the answer, enter the answer, and then they get feedback (usually a simple right or wrong) from the computer. In a more sophisticated computer program, there might be more extensive feedback, including additional learning activities and/or follow-up questions as a result of the student's quiz performance. So, yes, that's very active. More active than just reading.
That is not to say that reading is entirely passive, but reading with some kind of machine-graded quiz is more active than just reading alone. Likewise, if a student takes notes or highlights while reading, that is more active than just reading. If students write up responses to what they read, or if they share the reading with others, that something active. If the student annotates the reading or modifies it, then the student's learning is more active than just reading. Hence the term "learning activities."
But what does it mean for learning to be interactive? The way I see it, the "inter" prefix there requires that there be two or more people interacting with one another (the Latin word inter means "between, among" as you can see in this Latin-English dictionary). So, taking a quiz which is graded by the computer is not interactive; I am not prepared to accept the surrogate human intelligence of a computer program as a sufficient substitute for a real human presence in order to call that "interactive." Active, yes, but not interactive. If the student takes notes, that is active; if they share their notes with others, that is interactive. If the student bookmarks the reading, that is active; if they share the link with others, that is interactive. If the student annotates the reading, that is active; if they read annotations made by others and share their own annotations with others, that is interactive.
I value active learning highly, and I value interactive learning even more highly. When I look at tools for learning, I value tools that promote active learning, but I value tools that promote interactive learning even more highly. It was refreshing for me today to have to think this through and spell out my assumptions more clearly, and I hope I can make use of this distinction as I discuss different learning tools in future posts at this blog.
Meanwhile, I should also note that one of the things I value most highly about Google+ is the high degree of interactivity there. I have decided it is important for me to keep this blog as a kind of public record of the tools I use in my teaching and the teaching goals that prompt me to choose these particular tools... but I've never experienced interactivity in a blog space that is anything like what I enjoy every day at Google+! There don't have to be lots of people... but it does take two to tango - and likewise it takes two to interact. :-)
Nos duo turba sumus. We two are a crowd. (Latin saying: details here)