Seeds vs Leechers
Seeding and leeching are two activities that are connected with P2P file sharing via torrents. A seed is a complete copy of a file from which other users can download. A single torrent can have multiple seeds, allowing downloaders to obtain pieces from different sources and increasing total speed. Leechers have a mixed meaning as it was initially coined to describe people who only download but not upload, thereby impacting the overall speed of the network. Currently, the term leecher is also used to refer to people who do not yet have the complete file, regardless of the download/upload speeds; also referred to as peers.
The number of seeds and leechers on a given torrent can affect the speed that you can get when downloading a file. A file that has just been put-up with only 1 seeder and thousands of leechers would have dismal speeds. After a few hours, some may already have finished downloading the file and has started to seed, thus improving the speed for everyone else. When the number of seeds outnumber the leechers, you can expect a much higher download speed than when the torrent was started.
This also shows another aspect of seeding and leeching. After downloading the complete files, leechers instantly turn into seeders. They no longer take up bandwidth but provide it to those who have not finished yet. This is encouraged and users are urged to maintain a 1:1 download to upload ratio as a minimum. Others opt to keep seeding even after they have exceeded the minimum. True to the original meaning of the word leecher, some people do remove the torrents to stop uploading while others intentionally modify their clients to prevent it from uploading even when they are still downloading. This is a practice that is discouraged and some networks are beginning to implement ways to prevent these types of leechers from downloading at high speeds if at all.
The health of the P2P community lies in the generosity of each one in the network. Despite a few errant members who refuse to share for whatever reason, most still do share their upload bandwidth so that others have a faster and less smoother downloading experience.
Summary:
1. Seeds are complete copies of a file while leechers are those who are downloading more than they are uploading
2. Seeds generally increase download speed while leechers lower it
3. Legal leechers become seeders once they finish downloading
4. Seeding is encouraged while leeching is discouraged