.COM is used for commercial and personal sites.
.NET is usually recommended for companies involved in Internet infrastructure.
.ORG is recommended for Non Profit organizations.
However, there are some similarities in hosting the three domain names:
One can use only letters, numbers, or hyphen ("-") as characters for the site
The domain name cannot begin or end with a hyphen
Two hyphens cannot be used together
The domain name must have less than 63* characters, not including .COM, .NET and .ORG
* .com, .net and .org domain names exceeding a total of 26 characters are supported by most of the web browsers. However, certain web browsers, email programs and other Internet related applications may not support domain names over 26 characters.