Trademark dilution, unlike trademark infringement, concerns the protection of a trademark, itself.  Whereas trademark infringement protects trademark owners against marketplace confusion, trademark dilution protects famous trademarks from being weakened in cases where no one would likely be confused.  The law recognizes that certain trademarks are so strong, and so famous, that no one but the senior trademark owner can use them as trademarks.  Think Microsoft jeans for jeans that are super soft and comfy.  They’re “micro-soft.”  Find another name!  Jet Blue toilet cleaner isn’t going to work either.  These brands are famous.  Any use by anyone who is not Microsoft or Jet Blue is going to either tarnish or dilute the trademark’s ability to serve as a sole identifier of source.  If you have any question whether the use of a trademark might dilute another mark, you should consult a trademark attorney.