About the project

CoJeCo.cz (WhatIsWhat.net) Encyclopedia is a privately owned comprehensive online encyclopedia. Czech OPTIMUS s.r.o. company is the sole holder of the copyright to the content of the encyclopedia and all rights arising from the concluded license agreements. The encyclopedia was created on the domain cojeco.cz (later on the English domain whatiswhat.net) in the summer of 1999. It was opened to the public on 14 March 2000. It is, to our knowledge, the longest-running original online comprehensive encyclopedia project in the world. It was given an open editorial interface and launched as a community project for volunteer authors. After a short period of time, back in 2000, the community administration was closed due to the insufficient level of contributions, contributions from volunteer authors were rejected, and further content development has since been handled by a paid editorial team of staff and outside experts. More about the team members in the About the Team article.

Some references

CoJeCo has cooperated with a number of partners. A few examples for all of them:

For the Czech mobile operator EuroTel (later O2), we delivered encyclopedia content in one of the first ever WAP-based applications since September 1, 2000. On the same platform at EuroTel, we subsequently offered the Taháky (Cheating sheets) application - a learning tool for pupils and students.

On the initiative of Mr. Ivo Lukačovič (founder of Seznam.cz), in 2007 we successfully launched the delivery of CoJeCo encyclopedia content for Seznam.cz under the Encyklopedie.Seznam.cz section.

For several years we produced our own radio programs Minute with Encyclopedia, which we prepared and delivered to several regional studios of Czech Radio. Based on the texts of these programmes, we then published two illustrated books in travel format, each with 366 texts of the programmes.

Later projects that we were also happy to participate in include the preparation of quiz questions for the Logos gaming app, the most statistically visited wap app in the Czech Republic at the time, or the delivery of quizzes to Czech Radio, Brno regional studio, etc.


Years 2019-2020

For years, the CoJeCo.cz encyclopedia answered five to seven thousand users a day (160–180 thousand a month) with their daily continuous questions. Unfortunately, the old web design, although superbly designed in 2000, was somehow no longer understood by search engines in 2019. Thus, they didn't even attract as many users as they used to. That's why, for CoJeCo's 20th birthday, we brought responsive web design, i.e. web design optimized for all kinds of views. In addition, we've added some major enhancements in 2020. Along with a new way to browse content, just by scrolling with your thumb on your mobile or your index finger on your tablet. For the curious, there's a new time exploration feature with time range settings - explore it for yourself behind the detailed search button next to the search input box. Browse, search, read and help our efforts to collect, preserve and bring you quality information. Share our mission and pass on information from the CoJeCo encyclopedia - the How to cite CoJeCo article describes how to do this.

Last modified 17th of February 2023.