[The enterprise search] market is still nascent, and there are buckets of money there (just ask Microsoft or FAST.) Mark my words, boring as it might seem, corporate search will be a big deal. And...there will be interesting implications w/r/t transparency and the like once all those corporate documents are discovered by the internal crawler.John Battelle's Searchblog: Enterprise Search (Yaawwwwnnn)
Having worked at large corporations, I can tell you that more attention needs to be paid to the enterprise search market. Competitive intelligence, knowledge management, internal weblogs -- all these things need a tie-in to search as well. Heck, document management is something that many companies are still grappling with.
Weblogs, email, and P2P concepts are three things that will intersect in this space. Oh, and I guess I'll throw profiles in there as well: internal subject matter experts centralizing information but being connected throughout the organization with other communities of practice.
Since lots of corporate information is hidden in various other systems -- databases, groupware, etc. -- these systems need to be scanning the "deep web". But I think the missing piece is to take that information and not only return a link to it (if possible) but enable it to be published elsewhere and categorized, like the blogging model.