Updating Website

I am updating our web site and wanted to know if I need to resubmit it to each of the search engines? The url is not changing but most of the content is. How does a search engine normally update its information? Is this an appropriate question to post here? My apologies if it is not.

>> Is this an appropriate question to post here? <<

Nope, it isn't. This forum's for Open Directory Project ( http://dmoz.org/ ) related questions only. You'll probably find a few good forums in http://ch.dmoz.org/Computers/Internet/Web_Design_and_Development/Authoring/Webmaster_Resources/Chats_and_Forums/ though.

Most of the time you don't need to "inform" a search engine as it'll find the new content on its own - but how long it'll take is a different matter. Altavista can do it within 48hours IF you've paid for a listing, Google sometimes does it within 48hours IF you are a popular/frequently updated site (usually a month if not) yadda yadda yadda.