Up to April 2010 there are over 83 million .com domain names registered!
You can choose between many different types of domain name extensions, but the most popular by far (and often considered the most “valuable” as well – if you are considering domain names as an investment) is the .com extension. The vast majority of large companies use .com domain names and they’ve spent hundreds of millions of dollars branding the .com the right top level domain names in the minds of web users worldwide. In fact, .com names are so widespread that many people don’t even know that other domain extensions exist!
.Com domains can be bought or sold by anyone. Consider them the equivalent of prime real-estate on the Internet. Most companies place a premium on having a .com name over any other domain extension.
Other generic international TLDs (also called gTLDs) include .net, .org, .info, .biz, .name, and .pro. They’ve each earned a certain level of respect as top-level domains. You can think of these other extensions as distant cousins to the almighty .com. They may seem less desirable to a .com, but that’s not necessarily the case. In fact, the availability of these other TLDs allows webmasters to get a domain that would not have been able to otherwise get.
In terms of functionality, all of the above extensions are equal. This means that having a.com won’t help a website rank higher in search engines of get a higher ‘click-through’ rate. However, in terms of investment, the .com domains bring a significantly higher ROI. Statistically, .com names are worth more than 7 times what .net equivalents are worth.