“Subreddits” are roughly equivalent to forums on message boards and are based around a subject (such as /r/politics) or the process used to discuss a variety of subjects (such as /r/AskAnAmerican or /r/explainlikeimfive). Users visiting a subreddit see a list of submissions. Any user can create a subreddit, and the creator assigns users to “moderate” the subreddit; these users can delete content, ban users and set subreddit rules.

“Submissions” or “Posts” are items submitted by users, roughly equivalent to a “post” on a blog. Submissions are made to a specific subreddit (e.g., a submission to /r/politics about voting results in South Carolina). They can be original content (e.g., a user’s thoughts on one candidate’s health care proposals), links to outside content (e.g., a link to a news story about one candidate’s fortunes or a video of a candidate’s speech) or a combination of the two. (In this report, the term “post” is generally used in reference to submissions.)

“Comments” are responses, reactions, additions or questions left by Reddit users to a post and/or to other comments.

“Discussion threads” are all the comments left in response to a single post and/or to other comments under that post.

“Authors” are Reddit users who submit a comment or a post.

“Upvoting” and “Downvoting” are ways for users to indicate their opinion of a post or comment they’ve read. Users can “vote” on a comment (or post) by clicking an up arrow (to “upvote”) or down arrow (to “downvote”). When there are more downvotes than upvotes, a comment is said to be “downvoted” and, depending on a user’s settings, may not be visible in the discussion.

For more information, please consult Reddit’s FAQ.