HoPEc stands for “Home Page Papers in Economics”.
Started in early 1997 as a classified, publically-available list of economists with some of their contact data (importantly—homepage addresses, hence the name). In 2000 it became a web service, where economists registered themselves. The project used the RePEc data collection for documents’ database. Users found their works in the database and thus built their research profiles.
HoPEc is a direct ACIS predecessor and you may consider it a prototype for ACIS. Also, it gave us a lot of useful experience.