I'm wondering if it's possible to search words from a huge text instead of one or two words. Example:

If the actual text says:
Is it possible to search "walking" and "hungry" from one textbox or textarea?

Yes, It is possible.

Maybe you'd only search the longest words or something assuming that they are the most important words?

And here's a related article I put together (in case that might give you any ideas about how to search for each word in a list of words):

Classic ASP Design Tips - Search For Keywords on Multiple Fields
http://www.bullschmidt.com/devtip-se...iplefields.asp