Almost a century ago, Josias Braun-Blanquet developed his phytosociological approach for vegetation field study. At that time, nobody could foresee what the impact of this methodology would be for vegetation science as well as for its application in nature conservation. Hundreds of thousands of so-called relevés (vegetation plot records) have been made, collected in field books, and many of them have been published afterward. Some 20 years ago, the software package Turboveg was developed for the input, storage, and handling of vegetation data. Since then, many national and regional vegetation databases have been compiled, providing the basis for national and international classification overviews and other scientific studies. It is estimated that currently there have been more than 4.2 million relevés made throughout Europe, including 1.8 million relevés already available in electronic dabatases and about 45% of these available in Turboveg format. The computerized vegetation data have been shown to offer new possibilities for ecological research (a new branch of study, called eco-informatics), of which a number of examples will be discussed. Furthermore, the electronic data form a fundament for the compilation of ecological information systems. As an example of these, the information system SynBioSys will be discussed as a new tool for nature conservation and policy making, including Natura 2000.