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An Open Source Web Conferencing System

Overview:

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.

Variations:

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 http://pulse.cantonpl.org/. 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.

Features

• Backtalk uses a conference structure sometimes called "linear" or "Well-style" (because it was popularized by the Picospan software that ran on the Well). Thus, it is similar to such products as Caucus, Yapp, and Motet. It supports an unlimited number of "conferences", each of which can contain an unlimited number of "items" or "topics" which begin with a short article entered by the original poster, to which are attached a linear series of "responses".

• Backtalk maintains a login and password for each user, and remembers which articles a user has seen, so that only new material is presented on subsequent visits. A web-based account creation tool is included which can be configured for either open or validated accounts. It is possible to construct conferences that are accessible only to restricted sets of users. It is possible to allow people without logins to read conferences.

• If you have existing web tools that already create and maintain accounts for users, Backtalk can most likely be adapted to be accessable from those same accounts. It's authentication system is very flexible and modular.

• Backtalk's user interfaces are scripted. Four different reasonably mature web interfaces are currently available. These standard interfaces all have lots of configuration switches, and, of course, the scripts themselves can be customized. Scripts are precompiled for maximum performance.

• The user interfaces allow users to create their own conference "hot lists", forget items they aren't interested in, and search the conferences. The system remembers which items are the user's favorites and displays new responses to them first. Postings can be plain text or HTML. Tools to delete or edit old messages or retitle topics are available and can be enabled either for all users or for administrators only. Administrators can link items between conferences, and delete, freeze, retire or retitle items. Extensive "help pages" are available in the Pistachio interface.

• There are complete suites of web-based adminstrative tools for account and conference administration. There are also command-line tools for most operations. A detailed "How-to" manual is included.

• Backtalk's conference database structure is compatible with Picospan and Yapp, so it can run either stand-alone or sharing conference data with one of these programs. It can even generate non-HTML versions of messages for use by the Picospan or Yapp command-line interfaces. Some backwards compatible optimizations of the database have been done to improve performance.

• Backtalk is written in C and works on virtually any Unix-type system. No Windows versions are available. It can use, but does not require, MySQL or PostgreSQL.

Documentation:

• Latest Version 1.3.x Stable Release Documentation.
• Latest Version 1.4.x Development Release Documentation.

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.

Future:

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:

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.