When I think of linearity I think of a line; something going in only one direction. I also think that Lupton is also talking about something similar to this idea. What I think she means is that if writing is linear is when then the writing is flowing in one direction. The work starts at one end and finishes at another; there is not moving around or skipping around. She related this idea of linearity to speaking which made it a bit easier to understand the concept. Think about it; when you speak you don’t skip words, you put words together to form a sentence, then the sentences form a story. She gave examples like reading written text or watching a PowerPoint is linear. One could also thing of linearity as something sequential; one thing must go after the other to form ideas. In a PowerPoint you watch/read the first slide to understand the second slide and the thirds slide and so on and so forth.
I do not think that blogging is linear. I would also think that Lupton would agree with my statement. She says that some digital media is nonlinear. She says that nonlinear forms, “The Web is pushing author, editors and designers to work inventively with new modes of microconent (page titles, key words, alt tags) that allow data to be searched, indexed, bookmarked, translated into audio or otherwise marked for recall.” Blogging does just that. Bloggers use key words and pages on their posts. These things allow readers to redirect to other similar topics; this causes the readers to get sent away from the original text.