Each torrent has 2 categories of people you download from. seeders are the ones who have the whole torrent and shared it. leechers are the ones who have only a part, they download what they miss from the seeders, and at the same time share with others what they have already downloaded. theoretically, the more people shared a torrent, the faster you will download it (it's great to see it in new episodes of popular series, such as big bang theory, dexter, etc.). If the torrent has shared hundreds / thousands of people and yet you are downloading tens of kb / s, it may be that most people only have a part of the torrent. as a result, the remaining part can be withdrawn from a few dozen people, and when a few thousand people try to withdraw the rest, the speed of dozens of people must be divided among these thousands of people.