The following is a list of advantages having your own domain means to search engines, directories and link pages. Every item isn't relevant to every search engine, but taken as a whole, these are the advantages. Some directories will not list your site if you don't have your own domain. Some engines rate your site as 'more relevant' to a search query by virtue of having your own domain. Some search engines will rate your site as 'more relevant' to search queries if your domain name has a keyword in it that is part of the term being searched.
Consumers generally trust a site with their own domain over a site that is a sub-domain.
Smart companies are very protective of their image on the internet. Networking is easier if you have your own domain. Other business executives are equally susceptible to the same 'perception is reality' concept as the general consumer. Level The Playing Field. At first glance, this question seems to have an obvious answer, but there is hidden meaning to this question.