I look at it in terms of efficiency; sites like reddit are simply inefficient ways to communicate. They are good at making random connections and exploring new subject areas, and that is what I use them for: if I have heard of a subject, but don't know about it, I find a subreddit on the topic and subscribe.

As a tool for discourse, however, there is much to be desired; communication is lossy (many posts are simply not upvoted enough to be seen) and interspersed with noise (unrelated but "viral" posts). Google Reader is almost lossless; it maintains a buffer of all messages for 30 days and then archives them so that they are available in search results but not as unread items. If one reads every feed to its end at least once a month, then no data is lost.

Google Reader thus has the odd effect of making one commit; either you are subscribed to a feed, and read every post of it, or you are not, and never see it anywhere. I have not used Reader for more than a few years, and furthermore haven't conducted a survey of its users, but I would theorize that Reader users as a whole are more productive/active than non-users as a result. Perhaps it could be a question on the next LessWrong survey.