First you may wish to know a little bit about the different (more common) extensions used. Please read below:

*.com - It is the most well-known extension and preferred by all commercial enterprises. Typical to find this extension with a site that tends to sell an item/product.

*.net - Used by providers that relate to network(ing) or internet services.

*.org - Traditionally used by non-commercial websites. More for organizations and social networking websites.

*.biz - Used for business or corporate websites.

*.info - Informative websites.

When starting a new company, it may be best to purchase a bundle of extensions for your domain name. The more popular are .com/.net/.org, however, .biz and .info are rising in popularity. For example, you do not want the domain of mysite.com, and someone else registers the domain of mysite.org.