It is to help you in this that we have provided a list of major search engines and directories with links to their 'suggest a site' webpage. Auto submissions are submissions done by using an automated software. This software submits the details of your website automatically to many search engines and directories. It cannot do submissions to search engines and directories that require specific or category information. Examples of search engines to which submissions can be automated are Altavista, Google and Lycos among others.
Manual submissions are submissions that are done manually with the help of a human operator.
Manual submissions are suited for submitting details to search engines and directories that require specific information about your website. In addition, usually in a directory, one needs to first locate the relevant category suitable for the subject of your website and then submit the details of your site under this category. Repeated submission is really to ensure that your website has a better chance of getting listed. There are chances that it might get missed the first few times you submit. So it's a good idea to repeat submissions so that these changes are reflected in the search engine listing.