When you submit your web site URL to a search engines, you basically ask the search engine spiders to visit your web site and to evaluate it. If the search engine spiders cannot find anything useful on your site, they won't list your web site. It doesn't make sense to submit your web site again and again if it isn't search engine ready.
Search engines must be able to find out what your web site is all about. They need to find text and links on your web pages and they also need to find the keywords for which you want to have high rankings on your web pages.
Submitting your web site to search engines is important, but it is not the most important step in your search engine marketing campaign.
It's much more important that your web pages are optimized for search engines. Many web sites are designed in a way that prevents them from showing up in search engines.
If your web pages are not search engine ready, it's pointless to submit them. If the search engines index your web site at all, it will be listed on position 17,352 or worse. With a listing on that position, you won't get any visitors.
Before submitting your web pages to search engines, you must make sure that they are optimized for your important keywords and for the special search engine you target.
If your web pages are prepared for a special search engine and for a special keyword then it's much more likely that your web site will receive high rankings.
Make sure that your web pages contain enough text and that search engine spiders can find the pages of your web site trough normal text links. Don't use web site intros and don't use too many Flash elements on your web site. It is extra work to optimize your web pages for search engines but it is well worth the effort.