BitTorrent is an application that can download big files at an incredibly high speed with the help of other users. As with other file exchange programs, you can get downloads from other users. Each time you click on a BitTorrent link, you'll be sending other users the parts of the file that you've already downloaded, and the more you send, the more you receive.
In the case of BitTorrent, however, you won't find a search engine for new torrents or settings to configure the program. Instead, you'll have to find the downloads on several different websites that have torrent links. In fact, there are more comprehensive torrent clients nowadays, but if you're only looking to download files, without any extra features or high resource consumption, this is the ideal option.
It works in a really simple way: you can install it in just a few seconds, and then, when you click on a torrent link on any website, BitTorrent will open a download window. The program can pause downloads, resume them, and do unlimited transfers.