The expense of registering and supporting a domain name is minor compared to the expense of marketing your domain name and your business. The last thing you want is for someone else (usually your competitors) to benefit from your efforts and try to establish your identity. You will see competitors registering names close to yours, and trying to benefit from typos your visitors may make.

For example, someone registered internik.net to try and benefit from typos by visitors to internic.net which is a legitimate company.