Seeding means sharing a file(s) with other peers.  After a torrent job finishes downloading, you are highly encouraged to leave the torrent job seeding.  Although the length of time that you should leave the file seeding is not defined, it is recommended that you share until the amount of data you upload reaches at least the same as the amount of data that you have download, also known as reaching a 1.0 ratio.  You can view the ratio by enabling the ‘Ratio’ column by right-clicking on a blank area in the the header and selecting “Ratio”