A kind of prototype server for special file conversion and OCRing is the Any2DjVu server: http://any2djvu.djvuzone.org/ [[2] ]
A prototype for a metadata server is the MathNet MMM (Mathematics
Metadata Markup) server:
http://www.mathematik.uni-osnabrueck.de/cgi-bin/MMM3.1.cgi
[[11] ]
Both servers work via Web masks, but can also be driven (for mass production) by LWP scripts [3].