Chris Hastie speaks the gospel truth. People may know their email
interface for daily reading of new mail, but probably not for archival
browsing and searching! They're as well off using the Web for that
"advanced" application as they are anything else.
What's more, many of the IMAP servers and clients I've used perform
*terribly* when handed a truly huge folder. The thought of dozens or
hundreds of archive users all trying to access one big folder at once is
chilling. :) So you end up breaking into 2002/01, 2002/02, etc... and hope
against hope that the client supports recursive searches (Mulberry, Mozilla
and IE do not, last I checked).