I don’t know about you, but I have a lot of e-mail saved up from over the years. Whenever I need to search to find something, Outlook’s built-in search isn’t exactly up to the task. While most noticeably it’s not all that speedy, I think that it’s greatest shortcoming is that it can’t search over multiple Outlook data files.
That’s where Lookout comes in – it indexes all of your Outlook data files (and My Documents too, if you want) and allows you to quickly search for anything that you want. It’s searches are done very quickly, too.
Note that Lookout is still in Beta, but it’s been very stable while I’ve used it.