Why do you guys need an additional program to search your local e-mails when you could use the search feature of your respective e-mail client instead?
-qforce
Have you tried the built-in search feature of Outlook?

It's completely unusable for anyone who has accumulated more than ... oh ... 100 messages.
Moreover, why do you use e-mail clients at all? I, for one, use Google Mail, and am perfectly happy with its search capabilities.
-qforce
It's a different topic, but... Personally, I use a localized solution because I don't have high bandwidth available (512kbps max), so I'm better off retrieving stuff once and caching it locally. Also, what poor connection I have is unreliable.
For corporations it's even more significant (hello, open-source world: corporations really do exist). Obviously you want to be able to manage your own internal email. The bandwidth cost could be enormous, and more importantly, many organizations must guarantee privacy (HIPAA, Sarbanes-Oxley). And if they've got to have a localized client, then they can't rely on GMail's search.
On a more general note, are there any people out there who definitely need a desktop search app to locate images, music, videos, etc.? If so, then why don't you use your picture managers, media players, etc. to do that? Wouldn't that be a much more efficient and appropriate way to organize images, music, etc.?
-qforce
Why force people to learn multiple apps? It might be fine for me; I'm well-practiced at such learning, and might benefit from targeted optimizations. But what about for my mom? I think it's fairly typical for people to think that anything they got off the web or via email are all "from the Internet"; how do you explain to such a person when they need to use which tool? (I remember trying to explain to my grandfather, as he was scanning genealogical material, when to save as JPG vs. when to save as PNG. What's an instinctive selection to us is befuddling and nonsensical to "civilians")
More importantly, it's impossible to compartmentalize mail vs documents vs media, etc. A huge portion of my email contains attached documents. And a non-trivial portion of my docs contain embedded images and audio. So if one is to effectively find all email that contain a document that has an embedded image, one needs to be able to handle the whole chain, all the way down.