Sometimes when I type a keyword into a search engine, and get the resulting list of websites, I am frustrated when I try to click on a site, only to find that site can’t be found.
If the engine can’t find the site, how does it find the web adress in the first place?
The “engine” is not attempting to find the site, your web browser is. Presumably, the last time your search engine updated its index, that page existed, but it doesn’t exist anymore, so when your browser tries to fetch it, you get an error.
If you’re using http://www.Google.com for searching and the page doesn’t exist any more, you can still see google’s cached copy of the page. For details, see http://www.google.com/help/features.html#cached
Most search engines don’t “search” the web. They have the pages listed in their databases. So if the link they have listed is dead, you get the 404.
I don’t know.
I just came in here cuz I saw the title of the OP and thought it might be a new Cajun recipe 
That would be Fillet o’Flounder