What Does Leech Mean?
In computing, generally, a leech is an individual who drains resources, bandwidth, or data off a website or a network, often in an unethical manner. This term is often used in the context of peer-to-peer (P2P) networks. Here, a leech refers to an individual who downloads the files or data without uploading anything in exchange. Such a person is also known as a leecher.
Techopedia Explains Leech
The computing term leech is a derived from the pesky animal found in lakes, which attaches to their hosts and sucks blood. Leeching is not necessarily an illegal consumption of computer resources; rather, it refers to using an excessive amount of a resources without giving anything back. For example, in USENET newsgroups, leeching is not considered unethical as the newsgroup protocol does not imply equal sharing of data. People are free to download any file without sharing the same to other users. A P2P network is different – there is an unwritten code that if you download, you should also share your resources so that others can also make use of the data. Other examples of leechers include: