My co-supervisor, Michael Weiss, came up with this diagram expressing the interactions we have with people on Twitter.
Direct messaging is the most intimate form of communication, which we cannot track through the API without authentication (and then only for an individual user) as it is private. We have engagement through conversation and retweets, passive listening (also known as lurking) and ignoring. In reality, we probably move between these states over the course of our interactions, depending on how we use Twitter; sometimes communicating by direct message, sometimes retweeting or conversing publicly, sometimes passively consuming, and sometimes occupied elsewhere and not reading the stream. Only spammers, interesting only in pushing their content, will remain always at the outside – ignoring, not consuming other peoples’ content.