The trending or 'hot' algorithm is a bit different than the "top" algorithm. I believe you're referring to the 'hot' algorithm which is meant to take velocity

The trending or 'hot' algorithm is a bit different than the "top" algorithm. I believe you're referring to the 'hot' algorithm which is meant to take velocity into account. Velocity tries to abstract away contextual factors like subreddit activity, number of votes, etc. and represent how quickly, relative to number of participants, a post is 'rising'. The 'top' algorithm, however, is purely a factor of total vote (up - down) + time.