Saw this on http://on10.net/Blogs/jesse/natural-language-search-in-vista/ and found it very cool. 

Hard to find details though, but found some information on http://windowshelp.microsoft.com/Windows/en-US/help/73106209-6df0-432a-8cb7-df5d8ce02ec61033.mspx

See below for an excerpt from that page, it allows you to search your computer using natural terms...

If you turn on natural language search, you can perform searches in a simpler way, without using colons and without the need to enter AND and OR in capital letters. For example, compare these two searches:

Without natural language
kind: music artist: (Beethoven OR Mozart)

kind: document author: (Charlie AND Herb)

With natural language

documents Charlie and Herb

music Beethoven or Mozart

 
To turn on natural language search

1. Open “Folder Options”

2. Click the Search tab.

3. Select the Use natural language search check box.

Even with natural language search turned on, you can continue to use the Search box in exactly the same way. If you want to use Boolean filters or introduce filters with colons and parentheses, you can. In addition, you can use all the same properties to fine-tune your searches. The difference is that you can enter searches in a more casual way. Here are some examples:

•email today

•documents 2006

•author Susan

•pictures vacation