The ADS Abstract Service has been instrumental in changing the way astronomers search and access the literature. One of the reasons for the immediate acceptance of the ADS by the astronomical community when the WWW based version became available was the ease of use of the interface. It provided access to many advanced features, while still making it extremely easy to execute simple queries. Most of the use is for simple queries, but a significant number of queries utilize the more sophisticated capabilities.
The search engine that provides this access was crucial to the success of the ADS as well. The most important aspects of a search engine are its speed and its flexibility to accommodate special features. The custom-designed software of the ADS search engine proved that at least in some instances a custom design has considerable advantage over a general purpose system. The search speed that we were able to achieve and the flexibility of the custom design that allows us to quickly adapt to our users' needs have justified the efforts of developing a system from scratch that is tailored to the specific data set.
The ADS had 31 533 users issue 780 711 queries and retrieve 15 238 646 references, 615 181 abstracts, and 1 119 122 scanned pages in November, 1999. Since the start of the ADS we have served 311 594 261 references and 17 146 370 scanned article pages. These numbers speak for them self about the success of the ADS.
Acknowledgements
Funding for this project has been provided by NASA under NASA Grant NCC5-189.
Copyright The European Southern Observatory (ESO)