Domain Mart says that there is a new (but is it really new?) type of domain-name hijacking being carried out unnoticed. It involves third-level domain-names associated with affiliate programs.
For example, if you had been an online affiliate of, say, company xyz.com, your affiliate internet address could have looked like YourCompanyName.xyz.com. If you or xyz.com terminates the relationship, xyz.com might decide to assign your affiliate address YourCompanyName.xyz.com to a new entity that has no relationship to you or YourCompanyName. The new entity would use YourCompanyName to exploit its intrinsic value.