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An Open Source Web Conferencing System

Copyright 1996-2009, Jan Wolter and Steve Weiss
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Latest stable release: Backtalk 1.3.30 (Aug 10, 2009).
Latest development release: Backtalk 1.4.12 (Jul 2, 2010).


Backtalk is an open-source, web-based computer conferencing system that supports text-based, on-line discussions in structured forums. It is similar in style to Picospan, Yapp, Caucus, or Motet.

The words "conferencing system" have been used to describe many different things, so let's clarify what Backtalk is not. First, Backtalk is not a multimedia system. It is primarily text-based. There is limited support for importing images and such, but at it's heart it's primarily a tool to allow people to type text at each other in a structured environment. Second, it is not a real-time chat system. You wouldn't normally expect a response to your postings within seconds. It's more the sort of thing where you post a message, and come back later in the day to see if anyone has responded.

Backtalk is a mature program which has been heavily used at several public sites since 1996. In addition to providing a full set of user features, it also includes comprehensive administration tools, documentation and automated installation scripts. It is very efficient and extremely configurable. It is actively supported, with regular new releases still being made.

Backtalk was originally developed for use on two non-profit, public access conferencing systems. HVCN needed a stand-alone web based conferencing system usable both by people with modern browsers and by people with access only to lynx. Grex needed a web interface to its existing Picospan conferences that would run reasonably fast even on their enormously over-burdened machines. Thus, Backtalk was designed to fill some difficult and demanding niches, and to serve wide ranges of users. Since then it has been extended to support even wider ranges of communities, including school-aged children.

A demonstration site is available.


In addition to to the standard Backtalk conferencing system, there are some derivative packages also available:

Booktalk is a variation of the Backtalk system developed for the Canton Public Library PULSE system. It designed to be used in schools, with conferences for each classroom under the control of a teacher and all-school conferences shared by all. You can see the original site at Just download the backtalk, bubblegum, and booktalk packages and follow the installation instructions in the booktalk package to install them.

Fronttalk is a command-line front-end to Backtalk. The look and feel is extremely similar to the original Picospan program used on The Well and Grex (which is similar to the command-line version of Yapp used in many places), but the program is actually a specialized web-browser that makes HTTP requests to a Backtalk system to read and post to the conferences. This means that it can be run on any Unix system to access any Backtalk system on the web that supports it. Fronttalk is still somewhat experimental, but it is the only open-source Picospan clone that I know of.


For a long-winded description of the system, see the Backtalk feature page. Here is a summary:


Backtalk is thoroughly documented. The user interfaces are documented through help pages, not a separate manual. For administrators, there are several documents available. Two versions are on line here:


Backtalk may be downloaded and used for free under a standard Gnu Public License. The terms of this license allow its use by both commercial and non-profit organizations, but does not allow software developed using Backtalk source to be resold. Anyone interested in obtaining Backtalk under other licensing terms should contact the authors.

Backtalk is implemented in C. The distributions includes full source, and portable scripts for compiling and installing the system, together with extensive and detailed documentation.

Sites interested in hiring an expert to install and customize a Backtalk system may contact Jan Wolter.


Though Backtalk is very sound and reliable, and contains a pretty complete range of features, there are still a lot of things we want to do with it.

Which features appear in future development releases depends partly on what seems cool to us at the moment that we have a bit of free time to work, and partly on what new features paying customers want to see. Even if you aren't a paying customer, asking will sometimes get you a new feature.

Current work is focused on Backtalk's email interface. Doing this well is pretty challenging. The 1.3.x version already has the ability to send email messages, but that ability isn't used for much yet. The 1.4.x branch includes code to validate email messages, and to control the privacy of email addresses (both from other users and from spammers). Next step will to work on allowing users to request E-mail notification of new postings. We want to support both instant notification and digests.

Options to migrate more data into SQL will be added, as will support for additional SQL servers. However the conference content will probably not move to SQL, simply because there is no advantage to doing so. The existing files are well optimized for the specific queries made on that data. An SQL server is designed to process much more general types of queries, and cannot be as heavily optimized for this application as the existing files are. Add the communication overhead and frequent difficulties in handling arbitrarily large hunks of text, and it becomes clear that putting conference content in an SQL database is not going to be a win. On the other hand, as we develop options to put everything else into SQL, maybe putting content in too will become attractive.

Another goal is to develop a threaded interface.

Work on the Spanish-language interface has been halted due to a lack of anyone who wants it.

More Information:

If you have questions about availability, installation or anything else Backtalk-related send e-mail to us. We are happy to help.

There is also the HVCN design conference, a public discussion forum where Jan and Steve used to hash out Backtalk design issues. Feel free to join in there, but we have to admit we haven't been using it for a while, because only Jan is doing active development.

E-Mail Jan Wolter
Thu Sep 29 20:08:11 EDT 2005

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