By 2004, search engine submission services became unnecessary because the major search engines, "the big four", Google, Yahoo!, Microsoft Live and Ask.com, already had the ability to automatically discover new webpages by crawling links from other sites. Professional search engine optimizers, have stated that search engine submission is unnecessary. In fact, automated search engine submission may violate the search engines' terms of service, creating the potential for a site using such a service to be banned.[2] In addition, the remaining search engine submission services have been seen trying out alternate business models, leading to web server attacks on the submitted domain names.
The exception to this rule occurs when a new site under a new domain name wishes to be indexed. As inbound links have not yet been established, search engines have no way to automatically discover the new site. In this case search engine submission is necessary.