Unlike Web documents, email post boxes are not publicly accessible. That makes it impossible to index them at source - the servers on which they reside. Generally, email address databases are culled from addresses that appear in Web documents and Usenet posts. This constitutes a tiny fraction of all the post boxes out there. To make matters more complicated, email addresses are often abbreviated names.
Search engines can only match on relatively close hits.
So don't be surprised if your search turns up no information although you know for a fact that so and so has an email address. On the virtual level, the World Wide Web has quickly become the medium of choice for special interest groups. That has made it, among other things, a vast bulletin board for informing like-minded people about activities around a given topic both in and out of cyberspace. Most Web pages give you contact info for further inquiries. And many give you links to related resources.