Reply #53: It is a threat.

[hang a left]

http://en.wikipedia.org/wiki/Cease_and_desist
Cease-and-desist letters

A cease-and-desist letter is a letter demanding that the recipient "cease and desist from" continuing certain behavior. The behavior in question can include publishing materials or making statements that the letter's sender considers copyright infringement, trademark infringement, patent infringement, slander, or libel. The letter typically threatens legal action if the recipient continues to publish the materials in question or make statements similar to the ones in question. It is similar in form, although not in function, to a demand letter, which alerts the recipient to a pending claim for money damages, usually as a result of a tort or a breach of contract.

There have been criticisms from civil liberties and free speech groups that cease-and-desist letters are often used by wealthy individuals and corporations to bully their less-monied opponents into silence, as many people will comply with even an unjustified cease-and-desist letter due to their unwillingness to engage in an expensive lawsuit. Such groups call this a chilling effect on free speech.

In the US, a recipient of a cease-and-desist letter put in a "reasonable apprehension" of litigation may respond through a declaratory judgment proceeding in their own jurisdiction.