BitTorrent has been around for a while and like every other technology, it has evolved and become better. DHT, a form of decentralized distribution; Peer exchange, that allows a group of peers to share a file faster and so, several improvements have been made over the base protocol. One such feature called Web Seeding was implemented in 2006.
What are web seeds?
What seeds give the torrent client the ability to download torrent pieces/data from an http source in addition to the swarm. So if you have a file somewhere on the internet, you can simply add its link to your torrent. Now if the swarm is weak, the torrent client will fetch data from the http source. The advantage, of course, is that a publisher can create a torrent of a file which is already hosted on his server and not worry about seeding it full time, while the user can obtain the data directly from the http source or through the torrent. Either way, the user will get the data from the http source. However, if the torrent becomes popular and self-sustainable, the torrent client will fetch data from the swarm and only use the http seed for pieces which are not available or are deficient in the swarm.
This is a very good approach towards file distribution which can be used by artists, producers who distribute their content online. Using web seeds, they can keep their torrents alive for as long as their servers are up. A perfect balance between load-balancing and content availability.
How to use web seeds?
Adding a web seeds to a torrent is very easy. If you’re creating a torrent in uTorrent, just add the http (or https or ftp) link to the Web seeds box. Only http, https or ftp links will work. Also, do note that if the torrent has just one file, you can add its http link right away. However, if it’s a directory of files, you can add the http link of the directory in the Web Seeds box and the torrent client will automatically append the file names. If the torrent has just one file, the file names in the torrent and in the web seeds can be different. However, in the second case, where it’s a directory of files and only a http directory link has been given in as a web seed, make sure the file names in the torrent and in the http directory are same, because the torrent client will simply append file name and if they don’t match, the file won’t be web-seeded.
Pro tip: Want to share a file through bittorrent but can’t seed for a lot of time? Host the file on Dropbox and add its public link (or directory link) as a web seed. Your torrent will be alive as long as Dropbox is up (which is always)