. Editors.

A collaborative editor is a software application that allows several people to edit a computer file using different computers. There are two types of collaborative editors, real-time and non-real-time. Real-time collaborative editors allow users to edit the same file at the same time. Non-real-time collaborative editors do not allow editing of the same file at the same time, thus being similar to revision control systems.
. Instant Update was released for Apple Macintosh OS in 1991 from ON Technology Later, a version for Microsoft Windows was released as well, real-time collaboration allowing across these two operating systems. Instant Update relied on a work group server to coordinate documents updated in real time on multiple clients.
More recently, SubEthaEditis Mac-based, and leverages the Mac Bonjour communications platform. SubEthaEdit won numerous awards, and was initially offered free of charge. But later it became commercial because there were not enough voluntary donations to keep it free. The Gobby collaborative editor aims to be very similar to SubEthaEdit, and is cross-platform and open source.
The Web 2.0 phenomenon has caused an explosion of interest in browser-based document editing tools. In particular, a product called Writely saw explosive user growth and was bought by Google in March 2006 (now called Google Docs & Spreadsheets). It provides simultaneous edits on the entirety of a document, though changes from other users are only reflected after the client program polling the server (every half-minute or so). Another early web-based solution was JotSpotLive, in which line-by-line simultaneous editing was available in near-realtime. However, after Google's purchase of parent company Jot Spot in November 2006, the site was closed and no comparable Google product has been introduced. Google Sites was launched in February 2007 as a refactoring of JotSpotbut it lacks the multi-user real-time abilities of JotLive. The Synchroedit (rich text) and MobWrite (plain text) projects have since emerged as two open-source attempts to fill the in gap real-time browser-based collaborative editing