A pastebin is a type of web application where users can store plain text. They are most commonly used to share short source code snippets for code review via Internet Relay Chat. The first pastebin was located at pastebin.com, but other sites with the same functionality have appeared, and several open source pastebin scripts are available. Many pastebins allow commenting, where readers can post feedback directly on the page. GitHub Gists are a type of pastebin with version control.
Pastebins were developed in the late 1990s to facilitate Internet Relay Chat "chatrooms" devoted to computing, where users naturally needed to somehow share large blocks of computer input or output in a line-oriented medium.
On such IRC "channels", where the formatting clues are subtle, and several conversations can be closely interleaved, blocks of computer data nearly always "flood" the queue, even the entire screen, disrupting the intricate flow. Users are warned to use a "pastebin" or risk being "kicked" for "flooding". By using a web link to a pastebin posting, an IRC user can avoid being "banned" for flooding a large block of computer data onto the IRC channel. Instead, a reference to it is a one-liner, and the usual protocol of an IRC conversation.
A new class of IRC bot evolved. In a chatroom that is largely oriented around a few pastebins, nothing more needs to be done after a post at its pastebin; the receiving party awaits a bot to announce the expected posting by the known user.
Unforeseen uses arose for pastebins. Aside from sharing temporary blocks of what is, overall, unrelated computer data, pastebins are frequently used to anonymously publish texts online. Also since pastebins are relatively simple to implement, writing a pastebin web-application is regarded as a good exercise for programmers. Representative pastebins now exist for many programming languages including Lisp, PHP, Perl and Python.