I don't make a phone call to anyone, no need... because there is no action until they send me something in writing, and even then, still nothing occurs until they file with a court, because the law just isn't with a poster in regards to their content rights.
This has been fought in courts worldwide by big and small companies, individuals, and 99% of them lose, because as long as its not illegal, then its legal. Its like slander... you can call someone a moron all you want online, because you can't prove you weren't one / aren't one or the person is interpreting your text as being one. But if you said a person is a rapist, and they're not, then that is slanderous. Either way, the owner of the site cannot be taken to court if two members are slandering one another, because they must prove in court first, then a court will order the owner to remove the content. The owner has no obligation until such evidence and proof that something is slanderous, that is when they must act or are in breach of law themselves. Basically, a website owner is not a court and does not have a legal obligation to act as judge and jury for anything members post upon their site.
Outright slander is about the only thing that wins in court from websites... basically, if you post it online, then you just lost control of it by law.
Until it gets filed in a court here, I don't bother raising my eyebrow to it. It just annoys me that people are that stupid to begin with in order to make such threats so readily.