The Web has information resources of all kinds, but there is no single index to everything.
Some of the best pointers are the InfoSeek server, the Einet Galaxy, the Lycos catalogue, the WebCrawler, the CUI Catalogue at the University of Geneva and the Yahoo server.
If it's specific files you want, and you already know the filename or part of it, try Archie, the index to the world's FTP archives. There are some application-specific indexes as well, like the CTAN for TeX software. For meanings, consult the network acronym server. There is a list of local (UCC) Web information online.
There is no global directory of users yet, so to find people (eg their email addresses), try the experimental X.500 directory service at Chemnitz-Zwickau Technical University or AT&T (but remember not all countries participate in the X.500 project yet).
AT&T also run a non-X.500 search service using Gopher. The RTFM service at MIT runs a directory of people who have posted articles to the Usenet news service. This is accessible by email only: send a 1-line mail message to email@example.com saying
(replacing name with the name you are looking for). Many organizations now run Web directories of their own, so it's worth trying URLs like www.orgname.domain (replacing orgname with the organization's network name and domain with their likely domain name.