Web sites offering to "search" or assist a search are conventionally divided into search engines and directories, although there is a great deal of overlap. Submission to the former is easier. Directories slow down the process because they generally ask the submitter to look through their directories to find where their submissions would be most appropriate.
Most surfers use a relatively few leading sites and directories. Out of the hundreds of others, a number of secondary sites that may also be useful are also listed below. Some of these are called "specialty sites" because of topic, nationality, or language. The leading sites are far more likely to be used by browsers, but the sites of submitters are also more likely to get lost in them.
The submission process can be handled mechanically, or manually site by site. By using this site, you are choosing the latter method — which is arguably the most effective. Mechanical submission to many sites at once could fail for several reasons. Many search engines resist programmed submissions. What is entered cannot be tailored to particular sites if you use mass submission. Manual submission can be tedious, but not impossible. There are probably less than one hundred sites that it makes any sense to submit to, certainly not more than 200. Many sites are interconnected and search what is submitted to one another. There are many sources of information on search engines and submission. Some of the most useful are that for the Search Engine Watch Awards, WebMaster World, and the Listing for all Major and Minor Search Engines.
Many search engines and directories charge for submissions, but most have at least a "free submission" choice. Many search engines with free submission also offer various programs by which your site can be given preferential treatment in exchange for a fee.
The following lists concentrate on free submissions. It is hard to tell how much improvement is gained by paying requested fees. This could be a valuable way to spend money, particularly when a leading search engine or directory is involved. Most secondary search engines or directories that can only be accessed after paying a fee have been omitted from the following lists.
Ease of submission varies greatly. Some engines do little more than request your URL. Others have extensive forms. Some ask you to "join". If "membership" is free, this should not be onerous, but it probably means accepting lots of email with offers etc. Some offer almost immediate inclusion. Others suggest they will take weeks or months (part of this is to contrast their free service with faster, paid "express" service).
In the accompanying listings, the contact URL is generally the one the site has established for submissions, but in some cases the home page of the site is listed. In these cases, users will have to find how to get the submission page if there is one.