Share ratio –
The ratio is the amount of data a user has uploaded divided by the amount of data they have downloaded for a particular torrent (UL÷DL). A share ratio of 1+ has a positive effect on the user’s reputation because it means that the user has sent more data to other users than he has received. Conversely, share ratios under 1 have a negative effect.
BitTorrent is a file transfer protocol that enables you to download small pieces of an underlying file from many different peers. For instance, if you wanted to download a 1 GB freeware program, you can use BitTorrent to download it in 1 to 2 MB chunks from other people who already have the program
The BitTorrent ratio is typically calculated by dividing the total amount of a data you have uploaded for a certain file by the total amount downloaded. For instance, if you have downloaded 500 MB and uploaded 250 MB, your ratio would be .5.
BitTorrent client programs discourage users from “leeching”(downloading without uploading) by limiting download speeds if upload rates are too low. Achieving a higher upload ratio may improve download speed.
After you are finished downloading a file with BitTorrent, you can upload the file to other users, known as “seeding” the file.
It may be considered poor etiquette among the BitTorrent community to consistently download much more data than you upload.