If you have Google Analytics on your blog or website than you can check that these search engines drive traffic to your site even when you haven`t submitted your sitemap or site to them.
Only Bing and Google want you to submit sitemap. As so many people already using these search engines so we should not ignore. Most of them let you submit your site or blog.
|Submit Your Site to More than 100 Search Engines : eAskme|
How to Submit Your Site to More than 100 Search Engines :
How to Use Web Submission Sites :You just need to enter your site URL and email id in box and click on "Submit". Than click on confirmation link you receive in your email.
List of 5 Web Submission Sites to help you submit your site on other search engines.
These sites will help you index in more than 100 search engines. You should also check how to get 10,000 visitors everyday on blog or website ?
Do share your own views about search engine submission.