Definition: Submitting by hand to an individual search engine, rather than using an automated submission tool or service. Manual submitting is the more polite way to submit, and as such is less likely to land you in trouble with the search engines. But the best approach is not to submit at all and let the search engine spiders find your site through links from other sites to your site.
FirstClickSEO Commentary: We recommend manual submissions with any significant site updates. Too many can get you flagged for spamming.