Reddit (platform) enables the sorting of individual subreddits, Multireddit aggregations, user profiles, etc. by various criteria—namely /hot, /top, /new, and /rising.

/hot are the submissions deemed the best or most popular by the #redditAlgorithm (reddit); a rank primarily gauged from the tally of votes, number of comments, and velocity of acquisition. [1]

/top submissions can be sub-sorted to show those that are top in the last day, top in the last week, top in the last month, top in the last year, and top of all time. Looking at trends within the /top posts in a subbreddit is the best gauge for assessing the type and voice of content that'll thrive there. [2]

/new are the most recent submissions, from top to bottom. Looking at the frequency of new submissions to a subreddit will—compared to the number of subscribers—highlights the activity of the community. This depicts the degree of competition and reach available once above it.

/rising are the submissions that the algorithm believes to be /hot soon; these don't provide information as much as they provide practice. Guessing which submissions in /rising will become /hot based on trends identified in research of /top acts as a practice activity. It's a bit like playing Fantasy Reddit; the more you play, the better you get.

/best is Reddit's attempt to personalize the experience by surfacing posts from communities a user has shown interest in recently and by filters out posts users have already seen. [3][4][5]

Contexts

[1] Algorithm (reddit)
[2] Submission Checklist (Reddit)
[3] Best is the new hottness, reddit.com/r/changelog
[4] What we think about when we think about ranking, reddit.com/r/changelog
[5] Keeping the home feed fresh, reddit.com/r/changelog