It means you have to share back at least as much as you download in order to maintain a at least 1:1 ratio. So if you download a 60GB mame torrent on pleasuredome you have to also upload that 60GB to other users or they will ban your account. No one likes a person who deletes a torrent as soon as they have downloaded it without sharing it back, and that will get you banned from torrent sites for "hitting and running".
For example on this torrent site i have a ratio of 2.169 which means i have shared back more than twice as much as i have downloaded, as you can see from the other stats, 3.75TB uploaded and only 1.72TB downloaded, so i have shared more than i took, which means i have a good ratio.